You are right, of course. I only inspected the cfg file and I could not rename the antivirus subdirectory.
So, I tried one last time, with all features of the antivirus program switched off. I downloaded the installers for the scenery and the stand alone addon manager, after I had fully deinstalled both from my hard disk, answering YES in all cases. I checked for remining traces, but there was none.
Then I installed the scenery, after that the addon manager, made sure that the antivirus program had bglmanx.dll and couatl.exe as exceptions listed and started FSX.
It loaded the scenery files and updated the cfg file for them, then offered me free flight mode. I chose my ususal default flight, i.e. C172 in ELLX and waited for it to load.
when checking, there was nothing listed in the addon folder which had not been there before, moved to LSZH, gate 44, and found no buildings!
I think it is best to give up for now, as there seems to be something that prevents couatl.exe and the dll from being loaded and running and it seems to have to do with FSX itself not starting these addons for some mysterious reason.
So, please Umberto, do not spend too much time on this any more. I can live without the very nice Zurich scenery until some magic solution comes along.
It would be nice, of course, to have it, and it would be a good reason to buy some more of the FSDT sceneries, like KJFK or KLAX for instance.
Thank you and have a great weekend!
Juergen
(the old guy from the days of A.T.P. and AS2)