php 5 issues

[Chadi]

I upgraded to php 5.2.4 and now I get this when attempting to view threads

Fatal error: Cannot use object of type vB_Session as array in /home/user/public_html/showthread.php(1963) : eval()'d code on line 35

How do I debug this or trace the cause?

($hook = vBulletinHook::fetch_hook('showthread_complete')) ? eval($hook) : false;

Thats like 1963 from showthread.php

I disabled every plugin one by one, still go the error