Launch option rejected by Visual Pinball X
What it means
The games of this emulator that use its default program do not start from the frontend.
Why it happens
Recent Visual Pinball X 10.8.1 builds no longer have the -DisableTrueFullscreen, -EnableTrueFullscreen and -Primary options; an unknown option makes them show « Invalid Parameter » and close (Visual Pinball X source code). PinUP's default VPX script passes -%FSMODE% and -primary (PinUP documentation, VPX emulator page).
How Pincab Toolbox detects it
The launch script has PinUP's default shape; the program it starts is in the launch folder, is a Visual Pinball X 10.8.1 or later that refuses unknown options, and does not contain any trace of the option passed.
Check your own pincab
Pincab Toolbox is a free Windows scanner for Visual Pinball X and PinUP Popper. It finds and explains problems like this one. No account, no telemetry.
Download for freeCovered: Visual Pinball X (10.x) and PinUP Popper. Not covered: Future Pinball, Pinball FX, Visual Pinball 9 and the other frontends (PinballX, PinballY).