So ABRANDNEWME2012 about the import, did you already import your DC1 songs to DC2?
If so, I had already done that as well and my DC1 songs were in already in DC3 for me. If you have never imported before then I have no clue why it would say your code has already been used.
If you are still stumped you might try there forums. I had a couple of confusing moments when I was importing songs with my Rock Band music and found a lot of help in Harmonix's forums.
Hope it gets worked out!
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