Paolo, thanks for the suggestion.  I tried creating a new folder called "My Renders" and a sub-folder within that called "Lux Renders".  I then changed the destinations in the Output screen of Reality.  Saved the scene, closed Daz 3, reopened, and the same result . . . Lux not launching . . . no material file(s) being created.

BTW, I've used those folders, which include the "!", ever since Reality 1.0 without issue.

One more thing, which seems a bit trivial, but what the hey.  Within DAZ, when I click on the render tab, the Reality option used to have your logo next to it; ever since this problem started, it is just blank.