On September 4, 1993, at 1935 central daylight time, a Beech C-45H, N125MB, was substantially damaged near Fentress, Texas. One sky diver was fatally injured when his reserve parachute inadvertently deployed. The commercial pilot and the other nine passengers were not injured. Visual meteorological conditions prevailed for the local sky diving flight. During a telephone interview, conducted by the investigator-in- charge, the pilot stated that while the airplane was at 13,000 feet MSL, he reduced the left engine power to 15 inches of manifold pressure. He further said, as the jumpers prepared to exit the airplane, a prematurely deployed emergency parachute pulled one jumper out of the airplane. As the jumper's body struck the left horizontal stabilizer, the nose of the airplane pitched up and the airspeed dropped to 80 mph. The pilot and operator reported leading edge skin and ribs were damaged forward of the horizontal stabilizer spar. They further reported that the spar was bent and the upper skin was wrinkled aft of the spar. Examination of the reserve parachute SSE Sentinel Mk2000 S/N 7611, by the manufacturer, gives no evidence of any fault with the automatic signaling device (ASD). Their report is enclosed.