Import file problems, File could not be found.

I am trying to import waypoints from a Lowrance plotter. I used GPSBabel to convert the file to a .gdb file. the filename is now lowgarm.gdb.
I open the Homeport and click on "Import" in the file menu. I get the message :
/Users/martintopsoe/Documents/lowrgarm.gdb could not be found.

I did install the homeport on my girlfriends Mac and the same thing happens. One og my friends have a Windows PC and i did send the file to him. He can easily import the file. Does anyone know what can be wrong?
Brg. Martin, Denmark