Are you trying to enter information while stopped and in park?
If so and you still can't get to the menu, try ejecting the NAV-DVD from the player in the trunk, then start the car without the disc in the player. After that, turn off the car and reload the DVD. Try it then to see if it works properly.
The NAV player is mounted in the center of the trunk, at the top, under the liner. There is a small button to push for it to eject.
Remember, you can only enter address if the car is in park. So if you still can't get it to work, it's time to visit your dealer.