I repaired disk permissions, relaunched iTunes, clicked "Burn disc", selected 16x, and it pushed the CD back out a couple seconds later. I pushed the CD back in, exited iTunes, relaunched iTunes, and it went straight to "Burning Disc...initializing". When, after 20 minutes of nothing, I click the X to stop the burn, and confirm, the window changes to read "Canceling disc burn...this may take a minute or two". It sticks there. When I then try to exit iTunes, I get a confirmation window asking if I am sure I want to quit. I confirm (twice), but iTunes doesn't really quit, until I try a few more times and tell it again I really want to quit, at which point the system tells me I have inserted a blank disc and asks what I want to do.
Bottom line - this is still messed up. I want iTunes 7 back.