had the same problem. probably still have the same problem. internal disc drive stopped ejecting discs recently; i can hear the whirring and nothing happens. thanks to areticles and comments in apple support, have been thru all the steps described above, including "terminal" which was new to me. nothing worked.
today had itunes open and tried "eject disc" from the pull down "controls" menu. the disc popped out, just as if i hadn't spent more than an hour trying the same things over and over (yes, irrational to try over and over) a few days ago.
i don't know why it worked today. am out of warranty and don't want to spend $220 to have drive replaced, even tho that now seems like a reasonable amount after looking at the DYI instructions on ifixit.com - it looks like a delicate operation and like you could easily mess up the computer innards.
found a clamshell design (made by lite on and sold by amazon) which appealed to me bc there's no eject mechanism to break, and from reading lots of comments it seems like that mechanical eject mechanism is what breaks, rather than software. contacted mft to verify that it's mac compatible. drive works to play dvds, which is all i've attempted so far, but isn't recognized/mounted/whatever bc it doesn't show up in finder. now need to to post a question about that.