My P3 also was restarting when it was connected with Rhapsody. I tried setting the "Auto Off" feature to "Always On" and it still would restart in the middle of a music transfer. Then, last night, I changed the "Auto Off" feature to "5 Minutes" instead of "Always On" and it worked fine last night, transferring music without restarting.
If you haven't already sent in the unit for repair, you may want to try the "5 Minute" setting. I'm pretty sure this has something to do with Rhapsody, because I don't have any restarting trouble when I use MediaMonkey.