Got it working... user error :)
After uninstalling, and reinstalling, rinse, repeat... I realized the problem as soon as the red LED on the cable turned on - I hadn't been getting a good connection to the car port (DUH). In my defense, the cable I used with VAG-COM on my previous car (Audi) didn't have an LED, so never even thought about it. Only took 3 days to figure it out!
All that said, the cruise control works like a champ. And I can now reset the wheel circumference when I upgrade my wheels later this month. Happy days.