Thanks for the prompt reply. At least with respect to the FT-60, Commander was not open; at that point, it had not even been installed. IAC, I just went through the whole process again with the FT-60. Same error.
Seems curious to me that this would happen with two different cables connected to two different radios. I really do not see how it could be a cable issue. Driver issue, perhaps. That would be the only common denominator. The driver is FTDI 2.8.30.0, dated 7/12/13, and installed using COM4, as COM1/3 is reported "in use" (that would be for a Prolific driver/USB cable used with the UV-5R).