Last modified: 2009-05-27 18:47:42 UTC
The personal per_book gadget uses the fixed string "/wiki/" as the pathname to the personal per_book css and js filenames (see MediaWiki:Gadget-Personalper.js). This works on Wikibooks, but not on other Mediawiki installations, which may have a different path to the mediawiki code. The fix is simple. Replace "/wiki/" by wgScript, which holds the proper pathname prefix.
This is a script maintained by the administrators at English Wikibooks (I think darklama did this one? or maybe whiteknight). In any case, it's not part of the MediaWiki software. You can ask the user who wrote it (see the history of the code) or ask on http://en.wikibooks.org/wiki/WB:AA