vBulletin Error

[NoKSouLz]

Can anyone help me fix the following error:

vBulletin Message
Unable to add cookies, header already sent.
File: /var/www/gow2forum.co.uk/Public_HTML/includes/class_core.php
Line: 3254

I get this error when ever you click a forum section

It also says at the top:

Warning: array_sum() [function.array-sum]: The argument should be an array in [path]/includes/functions.php on line 4666

I have tried uploading all the original vBulletin files and still get the error..

What could be casuing it?

Thanks

Alec

[snakes1100]

Disable the plugin system in the vbulletin options --> plugin system, does the error go away?

If the error goes away, there is a issue with your hacks related to most likely a hack related to moderator permissions.