Our mediawiki was installed December 2006 on Mandrake 10 from a manual mediawiki 1.5.2 php 4.3.8 mysql 4.0.20
June 2009: updated to Centos 5.3 mediawiki 14.0 mysql 5.0.45 php 5.1.6 The weird things needed were:
chmod 733 /var/lib/php chgrp wwwserv /var/lib/php/session
in addition to the ever so confusion having to set the super user button in the form, despite that we use the special root's password for mysql. Also needed to reset the $wgEmailConfirmToEdit = true; otherwise anybody can edit pages.
Had to delete several hacker accounts, as well as their 'consumer links'. People do anything for money. Will this ever stop?
November 2009: once again had to re-install. But this time took a shortcut. mysql was created an account and database after it was populated.