It's not very clear if with "i tried to download but it does not load" you mean you are trying to downlading but it doesn't DOWNLOAD, or you are trying to download it, the download works, the install works, but it doesn't LOAD in FSX.
In any case, the problem it's almost surely caused by a bugged antivirus, which might block either the download or the loading or both. The solution is always the same:
- Download with the antivirus TURNED OFF.
- Uninstall the Stand-Alone Addon Manager. Reply YES when asked if you want to remove the Addon Manager and the Couatl Engine. Reply YES to both questions.
- TURN OFF your antivirus. Don't just exit from its interface, but turn off the real time protection. Actual wording changes between products, however, it's the option to scan every file that gets open in real time, without user intervention.
- Reinstall the Stand-Alone Addon Manager with the Antivirus TURNED OFF. Don't launch FSX yet.
- Configure the antivirus to exclude the following files from scanning:
YourFSXFolder\bglmanx.dll
YourFSXFolder\fsdreamteam\Couatl\couatl.exe
YourFSXFolder it's usually C:\Program Files\Microsoft Games\Microsoft Flight Simulator X, if you installed it in the default folder.
- Now you can turn the antivirus back on, and launch FSX.
- Check you are seeing BOTH the "Addon Manager" menu AND the "Couatl powered products" menu under the "Addons" menu.