If you restore, you will lose your unlock because iTunes will upgrade your phone to 3.1.3, which there is no unlock for at the moment. That's unless you jump through a lot of hoops and downgrade.....but that's another thread.
Here's a link on how to install a video ringtone. It goes into detail as to which sources are installed. It may give you a clue as to what to uninstall so you can get rid of it for good.