I have a Montana 600 with Backroads SD card installed. I purchased the Garmin City Navigator on DVD hoping to load it onto the Backroads SD card so I could flip from the Baclroads map to the City Navigator maps. I went to load the City Navigator maps onto the GPS unit and it starts the setup then it stops working and gives me an error " Garmin GPS updator has stopped working". Then it states"Contact Garmin" has anyone else tried to load City navigator onto a Backroads SD card? Has anyone else had similar issue wth City Navigator installation not working. Any help would be graetky appreciated. I tried installation on a Windows Vista and a Windows 7 computer same issue.