.htaccess issue

I have a plugin named – All In One WP Security installed on my website and it has written bunch of rules in .htaccess file and I can’t install a vbulletin forum on subdomain and getting the following error when trying to access forum in subdirectory –

The page isn’t redirecting properly

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

This problem can sometimes be caused by disabling or refusing to accept cookies.

Require to know what to edit in .htaccess file such that subdomain having vbulletin forum could be accessed from browser?