Success! After calling tech support and talking with Drew (outstanding support!), I was sent a version of the software install without the drivers which went fine, then directed to a website to download and install the drivers separately, also successfully. I'm up and running! Onward to connecting to WeatherLink network, CWOP and WeatherUnderground, then decide if this works fine or just send the AmbientWeather metobridge back.
UPDATE: and I'm up on WeatherLink (JWJordans). Now to figure out how to connect to Weather Underground.