As mentioned in the previous posts, it's a v-e-r-y simple fix (and somewhat common, too). There is a small microswitch inside the right side (facing radio) which needs to be jiggled a couple of times. Requires removing the black plastic guide which is held by 2 phillips screws. I've done it 3 times in 6 months.

This can be done without unplugging the harness, but if you do unplug it, MAKE SURE YOU HAVE THE RADIO CODE BEFOREHAND.

I don't think I'd bother taking it to the dealer. They'll simply reset the switch anyway.

My experience is that it happens if you let the cd hang for a minute after ejecting, or not inserting it smoothly. You can do it.