I restored my iPhone 3G[S] to 4.0. It is jailbroken via Pwnage Tool and unlocked on BB 5.11.07 via ultrasn0w

I set it up as a new phone, and synced all my music on.

For some reason, I cannot download any apps from the app store on my iPhone and iTunes gives me an error message (5002).

Anyone know what the issue is? I'm lost, I've check permission on iTunes on my computer (Snow Leopard on MBP), and my user/pass is correct. I can browse the store just fine, but can't download anything!