There are a few entries of 2007 uploads at Commons image table containing ' which makes an invalid title.
Such images are mostly unreachable, but if you do, it breaks. I have found them when using the API. When trying to get image info on a set where there is one of them a php error is produced:
PHP fatal error in /usr/local/apache/common-local/php-1.5/includes/filerepo/RepoGroup.php line 94:
Call to a member function getDBkey() on a non-object

Although if you advance to the limit you can retrieve the faulty name: http://commons.wikimedia.org/w/api.php?format=xml&action=query&generator=allimages&gaifrom=Eatmorchikn.jpg&gailimit=1

No new images with ' in the filename can be uploaded.

20080615 commons image table shows:
*Eaton's_Ninth_Floor_Restaurant.jpg
*Honest_Ed's.jpg
*Passing_the_time_at_Jeffrey's_Bay-_South_Africa.jpg
*Toronto's_Opera_House_-_In_construction.jpg

Other wikimedia projects may be affected.
External wikis may be affected, consider addition to update script.

Version: 1.14.x
Severity: major
URL: http://commons.wikimedia.org/w/api.php?format=xml&action=query&generator=allimages&gaifrom=Eatmorchikn.jpg&gailimit=1