backup fails

iPod Touch

Settings -> iCloud -> Storage & Backup -> Manage Storage -> (list of backups, "This iPod", click on it)

takes me to a page with a box that says choose the data you want to backup, spinning icon for a few seconds, then it just quits!

takes me back to my home screen.

Now this one:

Settings -> iCloud -> Storage & Backup -> Back Up Now

"Backing Up..." spinning icon, then "There was a problem completing the backup, please try again later."

We've tried again, and again, and again.

Eh, what's up Doc?

add'l info: connected to an iMac running Snow Leopard, latest iTunes.