At about 2100 eastern time, a Piper PA-28 made a forced landing while losing power on approach to Hinde Airport. The flight instructor and student pilot were not injured. The flight instructor said he told the student pilot to increase power while on short final, but the engine did not respond when the student pilot advanced the throttle. The airplane landed a half-mile short. The flight instructor secured the systems and noted the mag switch was already in the off position. The student could not remember if he had switched them off.