FS9 Flight Planner crashes Sim

When I have finished a flight and, sitting on the ground and select Flights,Flight Planner from the top toolbar, the sim crashes with the message that FS9 needs to close.This does not always happen but when it does I need to return to the Create a Flight screen in order to enter Flight Planner.I have the Sim on my C drive and My Documents is also on this drive so I don't think it is a communication problem as I first thought.It is most infuriating and always happens at the most inconvenient time.