During a vfr final approach, following a parachute jumping flight, to a private airstrip the engine lost all power. The pilot made a forced landing into a field. The owner/operator reported that the flaps remained in the up position at the accident site and that the pilot had stated the flaps remained in the up position during the approach and landing. The manufacturers’ procedures list full flaps for a shortfield landing. During the flare/touchdown the nose gear collapsed and the airplane came to rest in an inverted position. The cause of the power loss was not determined.