I've had the same problem with my Nano. Apparently iPod OS doesn't read filenames longer than 31 chars. so That option is mandatory as well as the option to use iPod style folder structure. If you un-check any of these you'll have all kinds of problems with playback

Once in the past, on my 80gb iPod, I allowed long file names. I had the same symptoms.

Options>Portable/Audio devices>(your)iPod>Device Synchronization>trim path or filename length to 31.

When I turned this back on and resynched, the problem went away.

You might think the iPod OS would be smarter (or at least I did) but you would be wrong......

I don't know how to help you, but you may get better luck asking this on the "need help with device syncronization" forum

I recently started using media monkey (MM). MM imported my music just fine. I hooked up a brand new Shuffle and successfully loaded it with songs. The Shuffle works fine. Then I hooked up my 40G IPOD (click wheel version) which I have previously managed using iTunes. Note that I have previously uninstalled iTunes prior to installing MM. When I connected the IPOD, MM saw my IPOD with its existing music. I used MM to delete all of the existing music which went fine (just figured I had to). Then I used the MM "send to" approach to load the IPOD which seemed to go well. With the IPOD disconnected, you can confirm and scroll through all of the loaded music. But, now when I try to play a song, the IPOD just starts skipping through the song titles and never plays anything. Any help you could provide would be appreciated.

Clarification, I am trying to manage this IPOD manually so all of the sync options are off. Maybe that makes a difference?