I had the same problem with the FNB connect app. I didn't feel like going through the mission of upgrading so I downloaded a jailbreak app from cydia called "Firmware 3.1.3 App" which makes the phone think it is running 3.1.3 firmware. Then had no more problems after that. Apparently 3.1.2 and 3.1.3 are practically the same so this is safe if you have a jailbroken phone.