I don't think these will fix the issue, but..
Update to the latest version of PinballX, V5.54 (you're only one revision behind but worth doing)
From the log you're running a 2 screen system?. If so you have DMD enabled in PinballX as well, disable that - 'DMD enabled' setting under Display Settings in settings.exe.
Then, can you see what happens if in Game Manager (or Database Manager) select not to Hide Backglass image on game launch. It may also be worth attaching one of the backglass media files (image or video).