This has been answered many times already: it's a known FSX bug. Sometimes, a newly installed module would fail when it has just been trusted.
The solution is ALLOW the module to run, then launch FSX again. If it still doesn't work, reboot Windows and try again.
If you told to FSX not to run the module, you need to undo this, by editing the FSX.CFG file, located at %APPDATA%\Microsoft\FSX, and removing all the lines under the [trusted] section with a reference to bglmanx.dll (remove the whole line), so it will repeat again the question to trust the module on the next start, so you can retry running it.