Then I would suggest to do the following.
Open your config.php and below<?php add this line:
PHP Code:
define('DISABLE_HOOKS', true);
So it looks like this:
PHP Code:
<?php
define('DISABLE_HOOKS', true);
/*================================================= =====================*\
|| ################################################## ################## ||
|| # vBulletin 4.2.1
Go to your ACP, disable this mod, In Plugins & Products, then remove the define('DISABLE_HOOKS', true); from the config.php
Then you can uninstall the mod since it seems to blow your site up.