I have this nasty issue after a P3d v5 reinstall.
Only happens with the Sim-wings scenery (Madrid Pro, Barcelona Pro, Ibiza Pro) i was able to install other Aerosoft products (Airbus and Geneve) without issue.
I try everything over here without result (reg check, UAC off, Controlled folder access, etc) even i try a new p3d reinstall.
Here the picture of the error message, and the options after i selected the installation place,
Lockheed Martin PREPAR3D V5.x