Nav. Operating system upgrade problem

[crann]

I'm a newbie and just picked up an e46 coupe with a DVD Nav system. I just tried to upgrade to V29.1 by downloading the .RAR file and burning the file. I burned the .mds with ImgBurn (the .mdf file would not burn) and tried to load it in my Nav DVD reader. The screen prompted a no-disc found message and eventually ejected the CD on its own (I tried loading it again with no success). I then copied the .mdf file and saved it as a .iso file type and burned it using Nero 7, someone said they tried that in another thread and seemed to work. I loaded it in my Nav DVD reader and the screen prompted a message that it was loading the CD, the screen went black and I waited about 15 minutes hoping that it was close to finishing. I waited another 5 minutes and ejected the CD myself because I thought maybe there was something wrong with the CD. Now my screen is still blank and I can only use my radio. Any advice?