[slappy]

Originally Posted by ElfMage

Yes, indeed. If your site has a php error log, any php errors will appear there.

It is possible that this issue is caused by vbWiki Std, or it may not. More information would be required.

Ok, I have found the source of the error by looking in the error log:

PHP Fatal error:  Allowed memory size of 20971520 bytes exhausted (tried to allocate 75 bytes) in /xxx/xxx/xxx/languages/Language.php on line 1775

This is what made the crash semi-random. I changed the memory limit in the LocalSettings.php, and the problem went away.

What I still don't know is what is taking so much memory. The problem only occurred when having the vbWiki extension active, but this could of course either mean that this extension takes up a lot of memory itself, or that it was just the last drop, but the real culprit was some other extension.

Oh, and one more tip, which I found when looking through the error logs. The following (non-critical) error in your code appears a lot in the error-log, so you might want to fix it:

PHP Notice:  Undefined index:  vbwiki_preferencestitle in /xxx/xxx/forum/vbWiki/vbWiki_Hooks.php on line 45