Found the problem, the installer was confused by the use of the "Layer" (otherwise a keyword) in the scenery area name.
I already fixed the installer, but I would like to wait another report from another user with a similar problem before uploading the new version.
In the mean time, if you don't want to wait for the update, just change the area title in your scenery.cg now named "Afcad Frist Layer" to something else like "Afcad Frist Layr" or so. As long as it doesn't contain "Layer" in the name, it's fine.
Updated installer will of course not be so easily confused...
