Urg – I’m just about to travel and my iPod is sick.
I found this in several places on the web – how to run the disk check:
If you want to run the internal full disk scan on your iPod:
Hold down Menu and Play until it reboots and you see the Apple logo
As soon as your see the Apple logo, press Rew/Fw/Menu and the center menu “Select” button all at the same time. That will start the full scan.