I have this equivalent issue, I point to the P3D envelope and exe document and the installer does not feature. Is FSX or P3D v3 required to "trap" the installer? I just have P3D v4 on my framework.

I recently had to uninstall FSX SE and reinstall it. When opening FSDX SE, I get a window telling me that scenery file 121 is missing and I need to click on it to continue. I then get a similar window for each scenery file through 132, having to click on each one. FSX seems to open fine after that. ...