You should probably make sure you've got GPSapp working, first, and mess with that a while before trying Roadmap+Gpsapp

Remember that Roadmap+Gpsapp doesn't show street names or have street routing. It's just moving lines on the screen.

I've replied to your other thread about getting Roadmap working. Make sure you actually loaded the road maps onto the player (they are huge), and followed the readme to the letter.