Use new computer - Never used for itunes.
Download itunes 9.2.1 (latest), connect phone in DFU mode;
1. Turn off phone when connected to pc
2. Hold power for 3 sec
3. Keep hold power and home key for 10 sec (don`t let go power from step 1)
4. Release power key but keep holding home key
After detecting in dfu it will show recovery mode in itunes, restore and it will download new 4.0.1 firmware and restore without error.