I'm having a problem using instant replay on fsx .

Hey everyone, I'm using a fsx and once i wanna use the instant replay option to take a videos using Fraps , it turns to black the screen i can still hear the airplane alive but the screen turns all black no display available ..

how can i fix it so I'll record some videos of my own landings etc...
if it doesn't works ?

Please help me I've tried several times same problem

I'm running win XP sp3
Fsx
airplane : ARIANE 737-800

I'll wait an answer to solve this problem ..
thanks