that was my first thought, too. you might be on the .215 leak*. the way to check is go to into settings -> about phone and check the System Version - it's like the fifth item down the list. the last three numbers before XT912 should be either .211 or .215.
but, if your error is that the "service isn't available", and not "you're all up to date", you might just have to reboot your phone to see if you can get a better signal, or possibly go to a place with a better signal. i don't think their service has been down for long, if at all, recently.
*did it even leak, or was it mined and released by the community? it's been so long, i honestly don't remember.