This sounds like one of the files on the unit is upsetting the unit. Try to get in there and pause the unit before it hangs, then pick a new playlist if you can (note down the track that was causing the problem).

If you had a serial cable I could suggest a lot of other things; if you've not got yours yet, mail [email protected] - he's sending them out to people whose units shipped without them (due to the cable suppliers' cock-up!)

Hugo