That's where RoadMap should save the google route. I'd verify that the trips directory exists. It should be visible on the device in the file manager. If the directory exists, you may be having a download problem. Verify your Internet connection.
Also, make sure your route only has 2 points- start and destination. You should see a red dot on the destination and a green triangle at the start, with a red line connecting them. Then on hitting 'fetch google route, you should get the merge dialog.

If none of that helped post back

cheers,
kernelpanic