I'm assuming you have older encrypted music from iTunes that you want to reimport. Depending on which version of iTunes you currently have, I would try to use a software program called Requiem.
Requiem is a program that decrypts your music (and videos, though not rentals) the same way that iTunes does, losslessly, and copys the decrypted version to a new file. It works great so long as the version of requiem you have is compatible with the version of iTunes you have. Good luck.
EP, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS