no DFU, no tethered option

Just opened my ATV2 today. Hooked to TV, updated the ATV software via on-screen menu. purchased aTV (black). Downloaded SeasOnpass. I follow the on-screen direction (select unteathered, it downloads a file, unpacks it, etc..). Then I plug in the USB cable and hold both buttons on my remote. Nothing seems to happen, and it never seems to go into DFU. Should I wait for an update or is there something I'm missing?

Thanks,

Luke

reading through other comments. Here's a small update. When I plug in my usb cable, it is NOT seen in iTunes. Sounds like that is a cable problem then right? (or at least the start of the problems). If anyone has a brand of cable that works, let me know...

Luke