Tried ten times and rebooted twice in the meantime. Then installed the addon Manager again. The problem persists, the same Bglmanx.dll error and P3D wouldn't start.
I can only confirm it's working fine here, so the only possible reason must be something wrong in your system. The first and usual suggestion would be:
- Download and install with the antivirus Disabled.
- Configure the antivirus to exclude the P3D folder before starting it.
Also, check if you have this key:
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\Prepar3d.exe
and remove it.