I'm sorry, but it's just not possible that, using the current installer, and with the Addon Manager reporting the scenery to be active, it won't show.
Do you have GSX installed too ? If yes, try to enable logging in GSX, restart the sim, go to JFK, and exit. Check the logfile at %APPDATA%Virtuali\Couatl.LOG and Attach it to a post, so I can have a look at it.