747-400 for FSX: Changing to crazy weight and fuel values during flight

Hello everybodyStrange things happened with my FSX 747-400. Every time the same place on the route from LFPG to LSZH during descent the weight and fuel parameters on FMC changed to unrealistic values. Then the values on left side of PFD strip and FMC weight and fuel values are blinking (PERF INI). A normal landing is not possible. There is no relation with panel state or so because it was a flight without breaks. After this I deleted all related files for this flight and started it new, including programming FMC and all values, new. The same thing happened on the same place! Never before I had such problems with the FSX 747-400. What happens with it?Thanks for help and happy Easter!RegardsMarcel