Strange message I cant decipher-Help iPhone

Is your phone Jailbroken?
HP G72 B66US 17.3 Laptop Windows 7 iPhone 4, iPhone 3G, iPods and other Gadgets.

I Can Help:
1: Are you on contract or payg
2: Is this a iP4 or 3GS
if you are on payg it is a message saying ether your credit is low or you have a offer availble from 3.
it is not being decyferd by your phone properly.
2 reasons why this might happen:
sim wasnt brought with the phone
jail broken phone
Samsung Q45 Windows 7 iPhone4 iPad AppleTV iPhone3GS iPodTouch1stGen iPodClassic120GB VariousiPods

Thanks for your help everyone! I really appreciate it!
The phone is an iPhone 4. Its not jailbroken. Im on 3 Pay as you Go. Ive had the phone since they came out, and Ive never had a message like this before.
While the sim wasnt bought with the phone, since the Phone came from Apple and the Sim from 3, but it is a sim that was made for the iPhone and Ive not had any problems with it.
There is plenty of credit on it too, I only topped it up a few days before
Is there any other reason why this could have happened? Is it common? Is it likely to happen again?
Dell Windows 7

On a non-jailbroken phone, I am truly without a clue... will have to think about this for a while.
Anyone else?
HP G72 B66US 17.3 Laptop Windows 7 iPhone 4, iPhone 3G, iPods and other Gadgets.