So, I no longer get the error message mentioned in my post immediately above.
I have reinstalled the app in a sub-directory of the C:\ drive and I have the lower thirds app working sort of.
When I mouse click the Lower Thirds 1, 2, 3 or 4 "on" button - the appropriate box gets a blue border and its lower thirds text appears on the screen.
However, the Hotkeys are not working. I can see them on the list of Hotkeys; however, Shift + 1, 2, 3, 4 does not work. I suspect they're still looking at the prior incorrect installation's location.
I'm loathe to uninstall the app as it's taken such a long road to get it installed so that the Lower Thirds appears on screen.
Any ideas?