hi , i have fatal error problem too, its always come and always after 20 minute or more out in the flight, i try everything that people say, but nothing help...
the thing that help me was : i install FSUIPC4 4.86 , and now the fatal error never come again.
this software do that addones comunicate with hardware like yoke pedals and more, and i hear that people that have old version of fsuipc have problems in win7 64, fsx..
so for me was FSUIPC4 4.86 that i need too fix the fatal error problems.