Hi
It looks like you have a corrupt version of `G4VisExecutive.icc’.
I was not able to follow the above correspondence with @bmorgan in detail, but all I can say is: start again, download, follow the Installation Guide. Don’t rely on any videos - they are not official. If they help you, fine, but if not, go back to the official Installation Guide. There seem to be several videos around on the Web; they might simply be out of date. We, that is, Geant4, do not produce videos. Even Geant4 tutorial material might be out of date. Please simply follow the current Installation Guide.
John