I just got a Garmin Dakota 20 and I am trying to upload tracks sent to me for a trip. I uploaded from my computer to device. When I click on click on the route, then click view map, then GO!, it says "Route calculation Error: Maps do not have routable roads in this area". Then I click OK and it shows the map with big arrow with a flashing question mark. did I miss a step to upload map and make it work correctly?