First, you should remove the manual installation folder you added, because doing this, you created a conflict yourself, since there's probably now a double area, which creates all sort of problems, like scenery disappearing, double objects and default scenery popping out.
Remove the folder you created, and also remove the area from the Scenery Library.
As you said yourself, the problem is caused by an error of your antivirus, which has mistakenly detected the software module the scenery needs to run as a threat, blocking it. If that software is blocked, no scenery will display. There were many threads about this in the forum, and the solution is always this one:
- Uninstall the scenery. Reply YES to the question "Do you want to remove the Addon Manager?"
- Turn the Antivirus OFF.
- Reinstall the scenery, don't launch FS9 yet.
- Configure your antivirus to exclude the following file from scanning:
\YourFS9Folder\MODULES\bglman.dll
- Turn the antivirus back ON, launch FS9.