I seem to be having the same issue. I've most of the FSDT Airports installed. Today I finally bought all of the Honolulu sceneries. Trying to install them I get the following message:
The following applications are using files that need to be updated by Setup. ... :
Couatl Scripting Engine FSX/ESP
Automatically close applications: yes.
Then I get the following notice:
Setup was unable to automatically Close all applications ... . Retry again or ...
However, retrying it again doesn't help. Ignoring it doesn't help.
I then downloaded the latest Add-on Manager, but I ended up with the same Problem.
Now (or maybe before and I hadn't noticed) all the buildings of KLAX (and probably all other FSDT sceneries) have disappeared.
What can I do? Thanks for your support.
Christoph