IPHONE 4 KEEPS FREEZING!

My new iphone 4 keeps freezing once it goes into auto lock mode. It stays on when it is plugged into itunes otherwise it freezes. Hard reset works to start it up but it just freezes again.
I have an unlocked iphone bought online from the UK and now i am in Dubai. I don't have any way to return it to the UK. Is there any way i can fix it myself or somewhere in Dubai???
Please help, i am so sad about this! I love the phone and want it to work !!