Eject Button Not working.

Since Leopard I think, just hitting the Eject button has another purpose.

In order to eject, you must now keep it depressed for half-a-second or a second or so.

Does option-eject work?
Does control-eject bring out the restart sleep+cancelshutdown menu?

Also:
Can you open/close/eject from a command within an application, example the eject button in iTunes?

All Permissions repaired, run a Verify Disk too,
now,
does it also happen when logged in from another User Account?

AxL, what exactly are you trying to Eject? CD? DVD? DATA Disc? HD?

Try these suggestion:

a. CTRL-Click the item on the Desktop and Select "Eject".

b. Reboot the Mac. Hold down the Mouse Button during the startup process. This will force the Optical drive to eject any media inside.

Let us know if this resolves your issue.

Try holding down both mouse (left click; if not try right click) and the eject key when trying to eject. And, [here are some other possibilities|http://support.apple.com/kb/TS2097] as well as the one I mentioned.

In order to find where the problem comes from before adventurously trashing any system file, I would like to know whether this problem happens only to one User Account or to all Users?
Also:
Please repair permissions and run a Verify Disk before any further troubleshooting.

In the meanwhile, no need to open iTunes, you can put an Eject button in the status bar.
Just go to
/System/Library/CoreServices/Menu Extras
and doubleclick the Eject.menu icon.

Try a different USB port, and resetting the computer's PRAM.