We found the problem, and it's in the FSX installer, some Windows update must have changed something in the default Windows XML parser to behave a bit differently than it used to be, and this seems to have confused the FSX installer.
It's fixed now. To get the latest installer files:
- Delete this folder, if you have it:
Documents\GSX_Installer
- Run the small gsx_fsx_setup.exe, which should download the updated files
Now everything works fine. Thanks !!!
