Then sorry, I'm afraid your situation is different, and we don't have other explanation for it.
Try this:
- Go into Control Panel, remove the Addon Manager, if you have an entry for it. Otherwise, remove both sceneries.
- Go into the FSX folder, verify that ALL bglmanx.dll files AND all the bglmanx*.dat files have been really removed. If not, removed them manually.
- Reboot Windows. Yes, this IS important. Do it, please.
- Turn the Antivirus OFF. Yes, this IS important.
- Reinstall the Addon Manager (or the sceneries you removed). Don't run FSX yet.
- Configure the antivirus to ignore the following files:
YourFSXFolder\bglmanx.dll
YourFSXFolder\fsdreamteam\Couatl\couatl.exe
- Launch FSX. At the request to Trust the Addon Manager, reply YES, to both question, the one by Windows and the one by FSX itself.
- If you get the error the 3rd party module can't be loaded, IGNORE IT, and ALLOW it to run, regardless of what it says. Don't worry if FSX crashes after having issued that message. It doens't matter.
- Keep trying and, allow 20-30 seconds between each tries. If after 3-4 times it's always the same, REBOOT Windows and try again. Yes, this IS important, do it please.