I had a similar issue, where I would get an error every time I synced the phone, and it would not complete. I ended up restoring the phone through iTunes, and then syncing all of my content again.
I think my problem came from some corruption from an interrupted sync. The cable was loose, and came of mid-sync. When I tried to re-sync, the error came up.
As long as you didn't jailbreak (hack) your phone, I don't think you have anything to lose by restoring it...