So one day my navigation decided to crap out and give me the error message informing me to contact a dealer for further assistance. did some research and tried the method of unplugging the battery. now that annoying message is gone and everything else seems to work fine. was able to input the security code but now as the navi was trying to update the system it would try to update but leave me with a message that says to check the cd. checked the cd in the trunk but all checks out well. i was curious to know if there was another cd or something that i needed for the installation or would it be something else in the car thats causing the navi not to read the disk

 

I have Been struggling with the same issue, trying to figure this out without having to drop a lot of money to fix it. I have tryed the same things as you and still no luck. I guess I will eventualy contact Alpine ( the manufacturer of the dvd unit) and they can fix it for about $150. I think the problem lies with the dvd player unit itself in the trunk. Let me know if you figure anything else out!