On May 18, 2003, at approximately 0935 central daylight time, a Beech BE-300 twin-engine airplane, N2SM, registered to and operated by OSO-RIO LLC of Houston, Texas, was substantially damaged during a runway overrun while landing on Runway 33 at the West Houston Airport (IWS), near Houston, Texas. The airline transport pilot, who was the sole occupant of the airplane, received minor injuries. Visual meteorological conditions prevailed for the Title 14 Code of Federal Regulations Part 91 personal flight, and a flight plan was not filed. The flight departed William P. Hobby Airport (HOU) at approximately 0915. The 5,200-hour pilot stated in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that while on the base leg for IWS, the annunciator light for the "low-pitch stop" propeller system on the right side illuminated. The pilot pulled the circuit breaker and left it out, as per the pilot operating handbook (POH). During the landing-roll, the pilot encountered a severe yaw to the right. The pilot added power to the right engine and realigned the airplane down the centerline. He then applied brakes and reverse thrust. The pilot stated that " it felt like I had no braking action and then felt the right side grab and brake, but not the left." The combination of right side braking and the "right low-pitch stop" system malfunction caused considerable adverse yaw, jerking the plane to the right. The pilot applied power again and straightened the nose of the airplane. He then made the decision to initiate a go-around, but at this point did not have adequate airspeed or runway length to safely accomplish a go around. He applied the brakes again, and the airplane immediately yawed to the right again, at which time the pilot was unable to compensate before the airplane caught the edge of the 3,953 feet long by 75 feet wide asphalt runway. The airplane went into the grass, where the pilot attempted to control the direction of the airplane and bring it to a complete stop. The airplane continued pulling to the right until it was moving in a sideway direction in relation to the runway. The airplane came to rest in a bayou located approximately 20 feet beyond the departure end of Runway 33. The pilot exited the aircraft unharmed. An inspection of the airplane by the operator revealed the "right low-pitchstop" system was not completely assembled, and the left brake line was leaking fluid and appeared to have been ruptured. Examination of the hydraulic brake hoses from the left and right main landing gears was conducted by Materials Analysis, Inc., and revealed that both hoses appeared to have been damaged with a hand tool. There was no evidence to suggest that the damage was caused by foreign objects striking the hoses, such as runway debris picked up the tires. No evidence of progressive failure was found on any of the fracture faces.