iphone "enter passcode" problem...

[quiktc3]

I was downloading apps yesterday with my new iphone 3g, and when i was messing with the programs, all of a sudden it says Enter passcode, and I cant even get into my phone now, because i never set a passcode for it. I restored my phone on itunes multiple times, and it fixed the problem only for a few minutes, and back to the "enter passcode" it went. Has anyone else had this problem? Any ideas to get this fixed? thanks