iPhone 4: Activation Session Has Expired?

[illegalprelude]

Anybody else experiencing this? Im trying to activate my iPhone 4 and everytime I plug it into iTunes, it tells me that my activation session has expired and that I need to unplug and retry but the same thing keeps coming up.

 

[Chupa Chupa]

Try restarting your computer.

 

[illegalprelude]

solved! Quit iTunes, took my Sim Card out and put it in, ran iTunes again and all is well!