Alan,
Ive tried what you said but still no joy, I had a response back from airnav support but they just asked if I had the globe symbol next to the aircraft in the list, which some do and some don't so this wasn't much help. I upgraded from version 4.03 and have today uninstalled the program and reinstalled the latest version and still no joy.
One thing I have noticed but not sure if it makes any difference is that when the program first starts and you get the small green box saying loading devices, checking framework mine then says RB1 found RB2 not found.
You also said about installing version 5.00.65 and then upgrading to 5.00.71, do you know where I can get a copy of version 5.00.65 as I cant find it on the website anywhere.
once again MTIA
Marc