Why does Itunes "Add Folder to Library" Lose Track Info?

I have thousands of mp3s on my computer. If I right click on any of them I can see the artist name, album name, and all that information. However, I just installed the latest itunes, and added the folder where I keep my mp3s. Over half of my mp3s show up with the artist, album, genre, and track number missing. Am I the only one having this issue? Am I doing something wrong? There's no way in hell I want to sit here and re-enter all that information that it should find in the mp3 file in the first place.

The reason I'm attempting to do this is I got a brand new Ipod. I can load the songs just fine using real player, but real player won't put album art, photos, or videos on my ipod. Not to mention that synching the ipod with real player causes the ipod to crash! So it looks like it's Itunes or nothing until real player updates it's drivers.