Hi Jon,
Just let me clarify what you want to do. Are you trying to move one
website hosting across from one account to another? Or is it you want to move a forum which is on your current web site hosting to a different domain name? From what you say, I'm guessing this is some kind of forum with a database attached to it?
Regarding the rename, is this just the the address for which the forum is accessed?
If you can tell me those things, I should be able to help you a bit more.
Thanks
Jonathan