I tried the change the domain of the forum but it wont work. How do I do this so the Forum will work on a different domain. I tired doing it through the General Settings but it still never worked.
You need to change the Board URL and your cookie settings. If you can actually tell us how it didn't work and what your new URL is we might be able to be a bit more specific than that
Yeah, you didn't update your cookie settings. You cookie domain needs to be .imperial-forum.com, edit it in settings.php and then in the ACP straight after.