You made me sad

I thought, this will end like this.
So, I'm trying to do a DFU restore since morning, but iTunes alwasy say: Error 1015. I installed libUSB, ran Error 1015 fix program, but the result is the same. I tried shift+click on restore button in iTunes, and browsed a fw, but doesn't work. In libUSB I can see, the phone is in DFU mode, but when I start restore in iTunes, it changes in recovery mode. It is a problem?
The highest iOS version what I can install is 3.1.3 with soem bug. Youtube application does not work and Cydia crashes after launch, so I can't unlock the phone. Maybe someone have an idea, how I put iOS 4 or Cydia? I can't SSH into the phone neither. It is exists a method to unlock the phone via PC?