mapping

[NXTUser]

I am trying to create a map and upload to NXT,which let the robot to follow. I use the codes:
wp = pathfinder.findRoute(new Pose(10,10,0), new WayPoint(16,11));
navi.followRoute(wp, false);
firstly get all the collection of nodes i need for pathfinding and then ask theNXT to follow,but when i run the programme,there is a error of class77,which is unreachable path.

thanks for any answear.