Put your iPod touch into DFU by following these instructions:
Connect your iPod to your Mac using your USB cable (random fact: it's a 30-pin connection into your iPod).
Quit (Command+Q) iTunes if it pops up.
Hold down both the power button and the home button for exactly 10 seconds.
Release the power button, but continue to hold the home button for at least 8 seconds.
Release the home button and you're in DFU.
iTunes will probably pop up with a little popup. Hit OK on the popup and quit iTunes.
Find tysiphonehelp on YouTube and follow his instructions for jailbreaking the iPod touch 2nd generation on the Mac (he's really helpful).
Seems like you did something wrong. I never went for those "one-click-jailbreak" deals, and always do it manually. Again, find the guy on YouTube and follow the step-by-step instructions.