[GPSNavX]

The Keyspan installer should be putting the driver (KeyspanUSAdriver.kext) in the Macintosh / System / Library / Extensions folder. You should not move the driver to the "Applications" folder. One important point is the Keyspan USB to serial adapter should be connected to your Mac before starting GPSNavX. Another is it may be that you have created a NMEA feedback loop with your autopilot. Make sure you are only transmitting to the Autopilot and that you are only receiving from the GPS. Select "Autopilot Only" in the GPS panel Settings drawer.