Vais unit problem, need help

I'm hoping someone may have had a similar issue and figured a fix. Already searched the forums and found nothing.

So I got my unit last week and connected no problem. used witha Nano and it worked great. Then i tried to connect a 40 gig model that I bought last christmas. No sound came from it. As a matter of fact the unit got stuck on one track and it did nothing.

I figured it could have been an Firmware issue. Next I plugged the Nano on and nothing, no sound came fro it. I was able to get tracks and a read on songs but still no sound. Anyone had a similar issue?

Thanks

Guille