Did you buy a copy or an original disc (there are also two types of disc, one of which does not work)? There are some issues reading map updates that I remember when I had my car. At one point I had to stop at an earlier revision because I could never get it to run. This is due to the hardware revision of the DVD drive. Go back to an earlier map revision and check the drive still works before you go to the expense of going to an audio dealer. Again subject to the year of your model some have upgraded the CIC, you will find lots of advice on this on the forum.
I have this same issue. It just stopped one day and I ran a DVD cleaner yet nothing. It does read non-nav disks like one of music files. I've just left it for now and plan on doing a CIC retrofit instead of fixing it.
CIC is a big and expensive job but worth it. It will replace your CCC (the main control system in the dash) and screen plus other components to the factory hard drive system used in 2010 models. Works great.