Right-click the VorpX icon in the system tray and select ‘Create Desktop Shortcut’, browse to your Steam folder on whichever drive you have Stalker installed installed, then to steamapps -> common -> STALKER -> Bin -> Win32, and select the XR3DA exe. This will create a shortcut on your desktop.
Go to configure Vorpx, in the General Tab make sure “Run Vorpx conrol as Administrator” is checked.
Go to the shortcut you previously created on your desktop. It should be XR_3DA vorpx and make sure you run that as an administrator.
This is the only way I was able to get the game running.