iFLY 747 autopilot not working

I saw the iFLY on the list of popular downloads, so though I would give it a shot. I tried the "no VC" version. Seems to work, but I can't get autopilot pitch modes to work. I tried all modes, and either in a climb or in level flight, they all go into a descent. The FMA shows the proper mode active. The best luck I had was in level change -- it desceneded about 5,000 ft then started climbing, but after getting up about 1,500 ft started descending again -- going back and forth like that. Never had any luck in alt hold, VS or VNAV. I aasume I must be the only one with problems?scott s..