I upgraded i Tunes to 10.1 and I've lost the datas of albums and authors

I upgraded i Tunes to 10.1 and I've lost the datas of albums and authors: with the previous version the datas of my CDs, that I put on an external drive like .wav files, i Tunes recognize authors and albums, with the new version I've got only one big "unknown album". How can I do to make it see those datas? Thanks!!!