THE ACFT WAS LANDED GEAR UP IN A PRECAUTIONARY LANDING AFTER A CONTROL DIFFICULTY IN FLT. ON BASE LEG A LOUD BANG WAS HEARD AND THE ACFT STARTED TO ROLL RIGHT. CONTROL FORCES WERE HEAVY SO THE OTHER PLT IN THE FRONT SEAT TRIED TO HELP ON THE CONTROLS. THEY THOUGHT THE AILERONS HAD FAILED, THEN THE PLT NOTICED RIGHT FLAP WAS UP SO HE STARTED TO RAISE THE FLAPS. HE SAID THE OTHER PLTS INPUTS CONFUSED AND ALARMED HIM SO HE GAVE IN TO THE PLEAS OF THE PASSENGERS TO 'PUT IT ONTHE GROUND'. HE RAISED THE GEAR AND TOUCHED DOWN BEFORE THE GEAR WAS FULLY UP ON PLOWED GROUND. THE ACFT SLID 200 FT ANDNOSED OVER. INVESTIGATION REVEALED THAT THE ONLY CONTROL PROBLEM WAS THE FAILED PUSH-PULL ROD (CESSNA P/N 120058-2) ON THE RIGHT FLAP. THEY FAILED IN OVERLOAD WITH A RUSTED FRACTURE SURFACE ON ONE WHICH INDICATED SOME PREVIOUS DAMAGE. THESE RODS WERE IN SERVICE 2040 HOURS. THE MOST RECENT INSPECTION WAS AN ANNUAL 19 TACH HOURS PRIOR TO THE ACCIDENT.