Check your FSX folder, do you have the following files ?
bglmanx.dll
fsdreamteam\Couatl\couatl.exe
For each file, right click on it, select "Properties", click "Details" and check the version. Bglmanx.dll should be 2,9,0,1 Couatl.exe should be 2.0.0.2090.
Then, selet the "Digital Signature", click "Details" and verify it's valid.