installed but won't run a LO

I was able to install the toolkit, with data base and to log in (using a user that is different from the administrator (!) I created a learning object but it won't run. Here are the errors:
featherlight.gallery.min.js:1


Failed to load resource: the server responded with a status of 404 ()
featherlight.min.js:1


Failed to load resource: the server responded with a status of 404 ()
highlight.pack.js:1


Failed to load resource: the server responded with a status of 404 ()
default.css:1


Failed to load resource: the server responded with a status of 404 ()
jquery.gray.min.js:1


Failed to load resource: the server responded with a status of 404 ()
featherlight.gallery.min.css:1


Failed to load resource: the server responded with a status of 404 ()
featherlight.min.css:1


Failed to load resource: the server responded with a status of 404 ()
xenith.js?version=3.12_(git_v3.12.25-2-g8259c8555):382 Uncaught TypeError: Cannot read properties of undefined (reading 'prototype')
at x_setUpLightBox (xenith.js?version=3.12_(git_v3.12.25-2-g8259c8555):382:581)
at x_pageLoaded (xenith.js?version=3.12_(git_v3.12.25-2-g8259c8555):406:230)
at Object.init (eval at <anonymous> (jquery-1.9.1.min.js:1:4902), <anonymous>:392:4)
at eval (eval at <anonymous> (jquery-1.9.1.min.js:1:4902), <anonymous>:1335:10)
at eval (<anonymous>)
at jquery-1.9.1.min.js:1:4902
at Function.globalEval (jquery-1.9.1.min.js:1:4913)
at init.domManip (jquery-1.9.1.min.js:1:60913)
at init.append (jquery-1.9.1.min.js:1:58249)
at init.<anonymous> (jquery-1.9.1.min.js:1:59789)
fa-solid-900.woff2:1


Failed to load resource: the server responded with a status of 404 ()
fa-solid-900.woff:1


Failed to load resource: the server responded with a status of 404 ()
fa-solid-900.ttf:1


Failed to load resource: the server responded with a status of 404 ()
featherlight.min.css:1


Failed to load resource: the server responded with a status of 404 ()
default.css:1


Failed to load resource: the server responded with a status of 404 ()
featherlight.gallery.min.css:1


Failed to load resource: the server responded with a status of 404 ()

As you see, most are CSS issues. But why won't it run?
Thanks for your patience.