Have developed rather large music library which has been working well until I recently downloaded a cd and it would not play on ipod but would play on computer. Message said that I needed to "restore" my ipod, so I did. Loosing all songs from ipod then it would restore to original, re syncing to reload ipod. Can not get it to complete loading. Gets about 1/3 through, stops, saying an error has occurred. Says files need to be reconfigured? Any suggestions?