The pilot reported that during two attempts to land on Runway 08 he experienced handling difficulties with the aircraft. He eventually landed on Runway 05. An inspection subsequently revealed the propeller had suffered a ground strike and the left main landing gear door was open. A gusting crosswind of 15 to 25 knots was reported at the time of the occurrence. Investigation determined that the locking balls were missing from the left main gear door actuator which would allow the door to open if hydraulic pressure was lost. An intermittent open circuit was also detected in the gear extend circuit. This defect caused the hydraulic pump to stop intermittently and may have resulted in the left door opening in flight. Had the left main gear door opened during the landing sequence it may have contributed to the handling difficulties experienced by the pilot in the gusting crosswind conditions.