There was a day when all I ever did was enter coordinates by hand. Create a new waypoint, enter the numbers. If you really want to be out caching, that would be one option. You could download EasyGPS. It's free and reads pocket queries (.GPX files). Configure its data communication settings before uploading waypoints to your GPS. If that app has a problem, too, then neither it, nor GSAK is probably the problem. In that case, suspect your GPSr unit or the cable.