Now that you have the files, try to disable EVERY other module in both files, by setting the <Disabled>True</Disabled> line. Of course, you must disable everything EXCEPT the Addon Manager ( bglmanx.dll in the DLL.XML file ), and the Couatl engine ( Couatl.exe in the EXE.XML )
Then launch FSX, and see if the error goes away. If it does, at least you would know the problem is caused by another module. You will then have to re-enabled them, one by one, and testing FSX each time, until you will eventually find which one is the cause.
But it would be useful to know even if, with all modules disabled, if the error persists. Please, try this at least.