w/o logging out, go into the process viewer, which is in theutilities folder of the applications folder, and forcequit anything that looks like it might be associated with the cd
I've seen that too, sometimes it looks like the OS itself is holding the CD.
I will try to control click the cd in a finder window and it will give that error
then if I try to eject the CD from the desktop (drag to the trash) it will works.
looks like there is too many way we can eject a CD and sometimes you have to try them all to eject.. ??
Sometimes when the CD willnot eject it takes and App like iTunes or the DVD Player to force the issue. Start iTunes and hit the eject button.
I had a similar issue with a Zip disk, only the damn thing never mounted and the manual eject hole is not accessible on the newer 'Quicksilver' boxes so I had to restart and finally the disk mounted.