When I used to encounter a problem like this, I would simply move the mouse to the "Addon Manager" tab, and select "Restart Couatl". When I tried to do this, there was no option for Couatl.
You don't restart Couatl from the Addon Manager. You restart it from its own ( "Couatl Powered products" ) menu. If you are missing the Couatl menu entirely, it's no wonder you are missing buildings.
As explained many times already on the forum, when the Couatl menu is missing, the most common cause is the antivirus blocking it.
- Go into Control Panel, Uninstall the scenery and reply YES to the questions "Do you want to remove the Addon Manager ?" and reply YES to the question "Do you want to remove the Couatl script engine ?"
- TURN YOUR ANTIVIRUS OFF.
With the antivirus still disabled, reinstall the scenery.
- BEFORE launching FSX, configure the antivirus to exclude the following files from scanning:
YourFSXFolder\bglmanx.dll
YourFSXFolder\fsdreamteam\Couatl\Couatl.exe
- Now you can turn your Antivirus on, and launch FSX
- Note if FSX asks permission to run the Addon Manager and the Couatl programs, reply YES to both
- When FSX loads, check if you have BOTH the "Addon Manager" and the "Couatl powered products" under the "Addons" menu.
If still doesn't work, be sure you are NOT running FSX into any of the "Compatibility" modes under Vista/Win7 ( right-click on FSX.EXE, select "Properties", select "Compatibility" and be sure NOTHING is enabled in that page)
If still doesn't work, maybe you also have inadvertently Un-trusted us as a Publisher, so nothing signed by us will run.
To fix this, go to the Control Panel, under "Internet Options", look for the "Content" tab, there should be a "Publishers" button, that will list the software publishers that you trusted, and another tab with untrusted publishers. If you see "Virtuali s.a.s", remove it from both tabs (especially if it's under untrusted)
