I am getting random fsx CTDs for no specific reason. Three times I got a g3d.dll module fault, once util.dll. The last one I had was in the opening menu itself with ntdll.dll fault. what is happening?

I am also getting random CTDs which seem to happen over North Wales area (GENX scenery).My error refers to util.dll as the faulting module - I have logged a case with MS so hopefully they can provide some clues!My config is :FSX SP2Add ons: Horizon VFR sceneryTraffic X SP1Various planesConfig:Athlon x4 3ghz4gb RAMGTX 260