Sorry but, if the Addon Manager and the Couatl menus are there and they are the most current version (they surely are, if you installed the Stand-Alone Addon Manager as last), it means everything is working and the sceneries must work, provided of course they *are* installed.
If they don't, then the problem must be something else entirely, check the antivirus for example, that is not blocking the installation of the current version of both Couatl/Addon Mananger, so you are still getting an older version for some reason.
The current version of the Addon Manager is 2.9.0.1 and Coatl it's 2.0.0.2098. If they are both running (their menus are visible) and the sceneries are installed and *are* the current version too, it MUST work, plain and simple.