Thankfully it's not a hardware problem. The issue occurs when the shortcut key I select is apparently similar to some existing shortcut. When I enter such a shortcut key combination, I hear the same sound as I do when later running the script, although it accepts it as a viable shortcut key combo. I have found, however, that scripts invoked through those shortcuts work intermittently. As an example, I used a shortcut key combo of "Alt + 8" for a script to transpose three staves up an octave. Apparently this is similar to something already in Finale because half the time it would transpose the staves DOWN an octave. When I chose a different shortcut key, the same script worked correctly & consistently.
I also determined that when FS will not execute something typed into the "Type a command" box at the bottom of the FS Palette & makes that aggravating sound, I can get around the problem by checking the box that displays the last script action & click OK. Then it works fine.
It took quite some time to recognize under what conditions these odd things occur but I have gotten past them now. I just wish the little frustrations were not so frequent & inexplicable. When everything works the way it should FS is extremely powerful & useful. It takes too much time to resolve the idiosyncrasies.