itunes won't sync all the songs

I am using iTunes 10. When I try to sync to my iPod Nano, it won't sync some songs that it synced before (giving me and it won't sync the new playlist. Does anyone have a solution? The errors I get for the songs are, "Attempting to copy the disk failed. You do not have enough access privileges for this operation." And then I get "iTunes could not copy "song name" to the iPod because an unknown error occurred (-5000)." The last error comes up with about 10 songs. I have given full rights to the music folder for all users.

I recently got a new computer and went from XP to Win 7. And I uninstalled and reinstalled itunes.