Dear Heinz, hope you and your family are well due covid 19.
I already download and tried to install FF Airbus 320U to Xplane 11.
I follow the same but Xplane is shutting down while FF A320F loading:
Unpack the downloaded zip file. You find it with your Aerosoft Shop account (if purchased with Aerosoft). That is where you purchased it.
Open the extracted folder "FLIGHTFACTOR_A320_ULTIMATE"
Open the included folder "Aircraft".
Copy the included folder "Flight Factor A320 Ultimate" into the Aircraft folder of your installed X-Plane 11 folder.