I'm having issues. I was stupid, and updated my jailbroken 1.1.1 iPod to 1.1.3 through iTunes, i.e., a regular update losing all of my apps etc. now I'd like to downgrade, re-jailbreak, and upgrade again. I have the 1.1.1 and 1.1.2 firmware, but I can't seem to get iTunes to install - I keep getting an "unknown error". Help?