Ipod needed software update but now wont sync.

I plugged in my ipod to add more music onto it and it told me that there was an error and to reset the ipod. so I did. Ive done it twice now and no matter what I do, it wont sync my music onto it. my pictures are on it but thats it. ive tried syncing just the music and it still doesnt take. what do i do?

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