I own a 1999 4.2 quattro with the nav plus system which is starting to drive me slightly bad and confused.

I have had the car now for just over two years and just after buying it i bought the latest CD to update the maps and worked fine until about two week ago

I get a "defective cd" error message on the top of the display but when i change the cd to the R.O.I and N.I its fine its just when the GB cd in it shows the message

Anyone out there experiencing the same problems?