I just got off a 2 hour call with Apple support. Even though there isn't iTunes Music store phone support after an hour and a half they eventually gave me to someone who works in the iTunes service department. If you have an @aol.com email address as your Apple ID, you cannot log onto the iTunes store on the Apple TV. The technician told me it's a bug they did not come across during testing and they're working now trying to resolve it. He said they're not sure if it's on the server side or if it's the v2 firmware. He said it looks like we'll be getting a 2.0.1 update very soon to resolve the issue.