Why not try a repair of FSX? Place the FSX DVD1 in the drive and select REPAIR when given the option. If you have Acceleration, you need to do a repair of that too. If you don't have Acceleration, you will need to reinstall both SP1 and SP2 too. This should help fix the situation.

I guess it is possible, that the error might be in the fsx.cfg, but I don't really know if there is anything in it's settings that deal with that.

Mark