Hmm, I may have spoken too soon. I have it installed but when I run the one action I need the process tuns just about forever and then gets killed, presumably by something within OS2008 that decides the process will never end. This is what I run

gpsbabel -i nmea -f GPSXX005.nmea -o kml -F GEPXX005.kml

(the test file is definitely there and only 94kb)

I was hoping that some others here might have enough experience with gpsbabel to tell me if I am doing something obviously wrong experience with OS2008 to know what it gives up on the process.