Hi NB
They are normally saved as GIF files in a folder something like this:
C:\AirNav Systems\AirNav RadarBox\Screen Shots
If you have installed the RadarBox software in the Program Files folder, and you are using Windows Vista or Windows 7, you may have to deal with the "virtual store" problem and hunt around your Users folders.
Try doing a search for "*.gif" (without the quotes) and see if that locates them.
HTH
Rod