I just bought a Avic-ni, and the guy I got it from gave me two discs. Supposedly for navigation. Both of them are the actual Pioneer discs, but whenever I have had the unit on whether listening to cd's or watching a dvd. when I put the nav. discs in, it will reboot, and when the unit comes back on and tries to load the discs, it will say insert proper discs, and/or read error. I know these are the correct discs because when it was in his car it worked fine, and I saw that he used these same discs. Is there a possible wiring installation problem, or could the discs being scatched a little have