TOPIC:

default permissions on xampp on Mac is more restricted than on PC. This crops up regularly and isn't really a xerte specific issue rather a xampp/mac specific issue. Try following the steps outlined here: stackoverflow.com/questions/9046977/xamp...missions-on-mac-os-x

HTH
Ron

Progress!
See attached screenshot - do I now click install? Haven't I already done that?

Sorry - still having trouble attaching screenshots.
This takes me to a page 'Welcome to Xerte Toolkits Installer' and asks me to begin installation - but haven't I already done that?

Yes indeed follow the steps and look out for the guidance that will be displayed if there are still further permissions or other settings to change.

So close! The MySQL Database won't launch, so I can;t get beyond the MySQL Database Creation page.
In case it is of any use, I have included the log below:

2016-08-26 12:51:12 787 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
2016-08-26 12:51:13 140735214272512 [Note] Using unique option prefix 'key_buffer' is error-prone and can break in the future. Please use the full name 'key_buffer_size' instead.
2016-08-26 12:51:13 140735214272512 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 933 ...
2016-08-26 12:51:13 140735214272512 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Memory barrier is not used
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Initializing buffer pool, size = 16.0M
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Completed initialization of buffer pool
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Highest supported file format is Barracuda.
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: 128 rollback segment(s) are active.
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Waiting for purge to start
2016-08-26 12:51:14 140735214272512 [Note] InnoDB: Percona XtraDB (www.percona.com) 5.6.28-76.1 started; log sequence number 1762733
2016-08-26 12:51:14 123145313034240 [Note] InnoDB: Dumping buffer pool(s) not yet started
2016-08-26 12:51:14 140735214272512 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 12:51:14 140735214272512 [Note] Server socket created on IP: '::'.
2016-08-26 12:51:14 140735214272512 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld: ready for connections.
Version: '10.1.13-MariaDB' socket: '/Applications/XAMPP/xamppfiles/var/mysql/mysql.sock' port: 3306 Source distribution
2016-08-26 18:07:12 827 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:07:12 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 896 ...
2016-08-26 18:07:12 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:07:13 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:07:13 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibg9uFM1' (Errcode: 13 "Permission denied")
2016-08-26 18:07:13 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:07:13 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:07:13 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:07:13 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:07:13 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:07:13 140735169613824 [ERROR] Aborting

2016-08-26 18:07:13 827 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:08:25 1072 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:08:25 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 1141 ...
2016-08-26 18:08:25 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:08:25 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:08:25 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibhZi8BS' (Errcode: 13 "Permission denied")
2016-08-26 18:08:25 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:08:25 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:08:25 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:08:25 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:08:25 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:08:25 140735169613824 [ERROR] Aborting

2016-08-26 18:08:26 1072 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:09:03 1238 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:09:04 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 1307 ...
2016-08-26 18:09:04 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:09:04 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:09:04 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibALoSVI' (Errcode: 13 "Permission denied")
2016-08-26 18:09:04 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:09:04 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:09:04 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:09:04 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:09:04 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:09:04 140735169613824 [ERROR] Aborting

2016-08-26 18:09:04 1238 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:10:26 1523 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:10:26 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 1592 ...
2016-08-26 18:10:26 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:10:26 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:10:26 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibXqfvgr' (Errcode: 13 "Permission denied")
2016-08-26 18:10:26 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:10:26 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:10:26 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:10:26 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:10:26 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:10:26 140735169613824 [ERROR] Aborting

2016-08-26 18:10:26 1523 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:12:21 1844 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:12:21 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 1915 ...
2016-08-26 18:12:21 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:12:21 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:12:21 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibrWAhKp' (Errcode: 13 "Permission denied")
2016-08-26 18:12:21 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:12:21 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:12:21 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:12:21 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:12:21 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:12:21 140735169613824 [ERROR] Aborting

2016-08-26 18:12:21 1844 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:13:23 2127 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:13:23 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 2196 ...
2016-08-26 18:13:23 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:13:23 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:13:23 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibVBTOaQ' (Errcode: 13 "Permission denied")
2016-08-26 18:13:23 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:13:23 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:13:23 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:13:23 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:13:23 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:13:23 140735169613824 [ERROR] Aborting

2016-08-26 18:13:24 2127 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:14:44 2492 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:14:44 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 2561 ...
2016-08-26 18:14:44 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:14:44 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:14:44 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibIOGciH' (Errcode: 13 "Permission denied")
2016-08-26 18:14:44 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:14:44 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:14:44 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:14:44 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:14:44 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:14:44 140735169613824 [ERROR] Aborting

2016-08-26 18:14:45 2492 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended
2016-08-26 18:15:48 2725 mysqld_safe Starting mysqld daemon with databases from /Applications/XAMPP/xamppfiles/var/mysql
Warning: World-writable config file '/Applications/XAMPP/xamppfiles/etc/my.cnf' is ignored
2016-08-26 18:15:48 140735169613824 [Note] /Applications/XAMPP/xamppfiles/sbin/mysqld (mysqld 10.1.13-MariaDB) starting as process 2794 ...
2016-08-26 18:15:48 140735169613824 [Warning] Setting lower_case_table_names=2 because file system for /Applications/XAMPP/xamppfiles/var/mysql/ is case insensitive
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: The InnoDB memory heap is disabled
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: Memory barrier is not used
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-08-26 18:15:48 140735169613824 [Note] InnoDB: Using SSE crc32 instructions
2016-08-26 18:15:48 140735169613824 [ERROR] mysqld: Can't create/write to file '/var/folders/dn/gdtp897s29x2lf97yxly29rr0000gn/T/ibBVTPlM' (Errcode: 13 "Permission denied")
2016-08-26 18:15:48 7fff75cad000 InnoDB: Error: unable to create temporary file; errno: 13
2016-08-26 18:15:48 140735169613824 [ERROR] Plugin 'InnoDB' init function returned error.
2016-08-26 18:15:48 140735169613824 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-08-26 18:15:48 140735169613824 [Note] Plugin 'FEEDBACK' is disabled.
2016-08-26 18:15:48 140735169613824 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-08-26 18:15:48 140735169613824 [ERROR] Aborting

2016-08-26 18:15:49 2725 mysqld_safe mysqld from pid file /Applications/XAMPP/xamppfiles/var/mysql/Claires-iMac.local.pid ended

Looks like it might be another permissions issue Can't create/write to file '/var/folders/dn/ e.g try opening permissions on /var/folders/dn/

this isn't really a xerte issue. Xerte will install quite happily on a web server with php and MySQL running and in your case xampp but you need to get xampp including it's web server Apache and database server MySQL/mariadb running first.

I'm not sure that error log is entirely relevant. But does the xampp console report Apache and MySQL as running or is the latter showing a red failed icon?