Topic: Bad HTTP Referrer (not mentioned in the sticky post)
I was changing the base URL in the admin console.
It was "http://domain.com/forums" but I wanted to change it to "http://www.domain.com/forums" but I accidentally left out the "." after "www" so it said "http://wwwdomain.com/forums" without the period after "www".
Now whenever I try to fix it and click save changes I just get a BAD HTTP REFERRER. Please help!