MyBB Community Forums

Basically, when I try to change my forum link from http://footiefanatics.co.uk/mybb to just http://footiefanatics.co.uk - it doesn't work properly, and says errors like "Cannot locate ACP *blah blah*".

How do I go about fixing this?

You need to change your Board URL in the Settings (General Configuration).
Also you will need to change your cookie settings.

How do I change the Cookie settings?

If you can't access the ACP edit them in ./inc/settings.php and then in the ACP afterwards. You'll need to change your cookie path to just /