I just came upon the solution – the Steam VR Home Beta Software is what causes the crash when you try to load up a game with vorpX. In the Steam VR settings, disable the SteamVR Home Beta, and everything works just great.
I noticed others with a similar problem – including some posts on the Open VR Runtime error. That cleared up with disabling the Home beta, too.
That information might deserve to be stickied somewhere.
Thanks for your reply.