Please help!!! cant make calls

[froggy212]

Hi, i just recived my stealthsim today, installed it in my iphone and i can receive calls, receive and send messages, but when i try to dial after like 2 seconds it says "call ended", any clues why i cant make calls? i already installed iworld cause the phone would crash when i dialed....can somebody help???thank you.
Please anybody tell me anything they might think it is, im going crazy here!!!!!