DURING CRUISE FLIGHT, THE RIGHT FUEL TANK RAN DRY AND THE ENGINE QUIT RUNNING. THE PILOT SWITCHED TO THE LEFT TANK, BUT THE ENGINE WOULD NOT RESTART, DUE TO THE VENT IN THE TANK FILLER CAP BEING PLUGGED. A FORCED LANDING WAS MADE TO ROUGH UP SLOPE TERRAIN IN LOW LIGHT CONDITIONS. DURING THE LANDING, THE LANDING GEAR COLLAPSED AND THE AIRCRAFT FLIPPED OVER.