Installed iTunes on new computer -- but I can't get the Library to fill

I keep all of my music on an external hard drive. I got a new computer and downloaded iTunes 8.0.2.20. I used the external hard drive for iTunes on my old computer as well.

But now I can't get iTunes to find or recognize any of the music on my external HD. I've changed the iTunes Music Folder Location to the external hard drive's music location. I've repeatedly tried to Consolidate my Library. My playlist names have reappeared, but my library and playlists are completely empty. (In fact, when I click on Library, all I get is a blank black screen in iTunes.)

Any ideas how to get iTunes to recognize my music on my external HD?