The pilot was on a personal cross country flight to a nearby airport. About 30 minutes after takeoff, the engine suddenly quit. Emergency procedures, including rotation of the fuel selector handle, failed to restart the engine and a forced landing area was selected on a rural dirt road. As the pilot was preparing to land, a school bus occupied the landing zone, and the pilot then selected an adjacent road. During the landing, the left wing struck trees located along the side of the road. FAA personnel reported that the fuel selector was in the off position, but placarded as the main tank position. The airplane's main wing fuel tanks contained fuel; however a header tank was empty. Maintenance personnel reported that on the evening prior to departure, the fuel selector was positioned on the header tank, which has a capacity of about 5 gallons. The pilot, who has about 10 hours of experience in the airplane, did not remember what fuel tank was selected. After the accident, the manufacturer issued a mandatory service bulletin requiring a placard detailing the fuel handle positions, and installation of mechanical stops and a movable gate to preclude inadvertent selection of the off position.