You must understand that, there's no way for us to troubleshoot a scenery from the Marketplace, because the installation is controlled by the simulator, and after the installation, the scenery files are encrypted, so we can't possibly check if something went wrong with it.
The only thing you might try, is to delete the CONTENT.XML file, which on the Steam version of the sim is located here:
%APPDATA%\Microsoft Flight Simulator\CONTENT.XML
This is sometimes required after a new scenery is installed.
