2. Check the position of the lock on the left side of the unit. All Apple Duo Docks have a locking mechanism to deter theft. The lock should in the open position (turned towards the "open lock" icon). If the Duo Dock is locked, neither the electric nor manual eject buttons will eject the Duo.
3. Verify that a monitor or other heavy object has not been placed on top cover of the dock. In some cases, heavy monitors can cause the upper case lid to bow, pinching the Duo inside the dock.
4. You can manually eject the Duo from the Dock much like you can manually eject a floppy disk. Take a key and insert it into the manual eject slot, located half-way back on the left side of the Dock. Push the key into the slot. This will disengage the Duo Dock locking mechanism. When the locking mechanism is released the Duo may need to be wiggled or nudged from side to side. Or you might try to gently push it further into the dock while holding the key which should release it.
5. If the above steps fail take the unit to your Apple Authorized Service Provider to have the Duo removed.