What is this error?

[Huskermax]

[29-Sep-2015 00:17:38 UTC] PHP Fatal error: Class 'vBulletinHook' not found in /home/hmforum/public_html/vbbs/includes/functions.php on line 4325

(vBulletin 4.2.2 Patch Level 4)

[Mark.B]

Please try the following:

To disable the plugin/hook system completely, edit includes/config.php and add the following code:
Just below

<?php

enter

define('DISABLE_HOOKS', true);

Do you still have the same problem?