New Pioneer AVH-P5000DVD Problem?

I just bought this unit, and had it installed for me by my local stereo shop. When I took it home it was working no problem.

The first time I started up the car after that, there was an error message on screen:

"Caution: Screen Image May Appear Reversed"

Now I know on other Pioneer models, this message appears while you view the reverse camera, but I don't have one!

Furthermore, when this message pops up, it takes up the whole screen. The message is displayed in the top left corner, and the rest of the screen goes black, no matter whether I'm listening to the radio, iPod, DVD, etc. Any source, same problem.However, I can touch the screen to resume whatever I was doing, unless I don't touch the screen for about 5 seconds, at which points it reverts back to the error message screen again.

I have looked through the manual but all it tells me is: "Pioneer recommends the use of a camera which outputs mirror reversed images, otherwise screen image may appear reversed"

What should I do?

Definately go back to the stereo shop that isntalled it. Maybe they accidently hooked up a wire to the spot for external camera or something liek that. All those shops should guarantee their work. I would take it back there before doing anything else. At least if nothing else he may be able to tell you what is wrong/what to do for sure.