After installing vBulletin on your hosting account, you might face compatibility issues depending on the vBulletin version. Log files on the server throw an error as below.
 EACCELERATOR can’t restore parent class “vB_Bootstrap” of class “vB_Bootstrap_Forum”
[Mon Aug 12 14:17:51 2013] [error] [client xx.xx.xx.xx] PHP Fatal error: Call to undefined method vB_Bootstrap_Forum::bootstrap() in /home/user/public_html/global.php on line 26
You will have to reinstall EAccelerator on your server with command below OR disable it for your hosting account.
#/scripts/phpextensionmgr uninstall EAccelerator
#/scripts/phpextensionmgr install EAccelerator
If you still face the same issue, cPanel has reported that it will be fixed within easyapache in next releases.
You can install vBulletin Forum with our cPanel shared hosting plans.