PinballX system program not found
What it means
The games of this system cannot be launched from PinballX while this program is missing.
Why it happens
PinballX's settings still name the old location of the program: it was moved, renamed or uninstalled after the settings were written.
How Pincab Toolbox detects it
The scan reads Config\PinballX.ini. For each enabled Visual Pinball, Future Pinball or custom system, it checks that the program named by the working path and the executable exists. If the drive of that program is not on this PC, it says nothing.
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. Partly covered, read only: PinballX and PinballY (their settings and game lists). Not covered: Future Pinball, Pinball FX, Visual Pinball 9 and the other frontends.