thats funny, that just happened on my beige G3.
most recent version of 10.0.x. Now I just put the cd into my firewire burner (LaCie - how to you actually say that, LaCie?), and the cd showed up.
I'm guessing that my internal ide cdrom will start working in a few mins. No idea why it stoped, I'm going to check the console and see if anything showed up. What kind of interface does the cube's cdrom use, anyway?