Bad HTTP_REFERER.

Bad HTTP_REFERER. If you have moved these forums from one location to another or 
switched domains, you need to update the Base URL manually in the database (look 
for o_base_url in the config table) and then clear the cache by deleting all .php 
files in the /cache directory.

I installed punbb into my main public_html folder so that the "front page" of my domain would just be the forums. I uploaded the contents of 'upload' into /public_html
The install went fine, but if I try to save any changes in the administration panel, it will give me that error.

I used phpmyadmin to access the o_base_url table but it looks fine? Its displaying my domain http://example.com/