iTunes error (-8753) when activating Genius.

When trying to turn on Genius, I get the following error after my library is scanned and the results sent to Apple (step 2): Genius results can't be updated right now. An unknown error occurred (-8753). I have actually spoken to Apple on the phone about this, and they didn't have any answers. The Apple forums have a couple posts with this error, but no answers. I have deleted all the iTunes files, reinstalled the application, started from scratch with the music library on a new computer, with different iTunes logins, all with the same result. I have a lot of music, over 60,000 songs, which is the only thing I can think of as the culprit, but otherwise I am out of ideas. I love the Genius function, and really want it to work. Anyone have any ideas?