My iTunes metadata is not importing with files!

I imported my iTunes library into songbird and the metadata for most of the files is messed up and all over the place. The names of artists and albums are correct, but the track numbers and everything else is either missing or different (some albums imported with all of their track numbers changed to 1).

This is incredibly annoying, especially because I had my iTunes library absolutely perfect, with all of the correct album art, track names/numbers, disk numbers, artist/album artist/album names...basically everything that could apply to each album.

I downloaded songbird so that I could connect my gigabeat to it (because it doesn't work with itunes and wmp sucks), and I was also considering switching over to it completely because of all the nice features, but if this problem cannot be fixed I will be greatly disappointed because there is no way I am going through the long process of edited the metadata of 100s of artists and albums of over 10,000 songs.

Can anyone help me? If I can't just import everything correctly, is it possible to get an app that will correct all the data?

Thank you.