i just recently bought an unlocked blackberry curve 8310 from an Ebay purchase as i had signed a new contract and wasn't qualified for an upgrade.
Anyway, I added the BIS add on to the line.
In trying to set my phone up, it appears that the "setup email" application has been deleted. If I'm remembering correctly this is where you tell the blackberry that you're on a BIS plan.. However, because the device doesn't "know" its on a BIS plan it isn't letting me use the facebook application. I'm getting a message that reads in the facebook application that reads "You are currently on a service plan that does not support this application. Please contact your service provider yada yada yada".
Are you able to resend your service books to the device? Below is a thread of how to send your service books. Maybe others have ideas, I see you posted this question in a couple spots.