GreenPois0n iPod Jailbreak not working?

I have attempted to jailbreak my iPod touch 2nd Gen with version 4.2.1, 4 times actually, but I still run into the same problem. After entering "DFU Mode" where I hold the sleep button for 2 seconds, both the sleep and home button for 10 seconds, and only the home then for 15 seconds, but afterwards, when i click "jailbreak" I see no progress in the bar, for as long as 25 minutes. I was told to hold the home button throughout the jailbreak, but that did not work either. I repeatedly set my ipod back to factory settings with no apps, no music, and no pictures. Can anybody help me?