Screen loading stops at language drop-down CentOS

I installed Xerte with Moodle 2.8 authentication on my local server (Debian Squeeze) and it runs perfectly. I then re-ran the install on a hosted site where CentOS is being used. Authentication and so on works fine. Everything also works when the httpd server is restarted. However after a while, when the tools are accessed again, the screen loading stops at the language drop-down (which is empty).

I've attached two screenshots. I can't find anything in the error logs - everything appears normal. I suspect one of the js files but am not sure how to proceed.

I checked the httpd log (was looking at the wrong one earlier): Failed to load language file for Xerte - en-GB/website_code/scripts/screen_display.js. Seems odd as that script doesn't appear to attempt to load a language file?

More data. The console log gives an error in screen_display.js at line 178: Uncaught TypeError: Cannot set property 'open' of null. The offending line is:

function sort_display_settings(){
document.getElementById("folder_workspace").open = true; // JS error

Yet more data: When I comment out the call to display_language_selectionform("general") from xerte/index.php around line 117 the rest of the page loads correctly. This function is in language_library.php.

<!-- commented out language selection php -->
<div style="float:left;"><?php //display_language_selectionform("general");?></div>

Thanks if you can help.
Richard

Thank you! I was having the same issue, again on a CentOS install, using the latest 2.1 update. It happens on the unstable version too.

I've commented out the same line, and so far so good. I think this started after a round of CentOS update applied a while back, I haven't been able to pin-point the cause yet. I initially thought PHP (tried 5.5/5.4), but after downgrading to 5.3 the issue got worse. Maybe its the apache version? (I'm on 2.2.15)