Hi Mark,
Welcome to the forums.
Sorry to hear you're having problems with your Rover 5 kit. On the
main product page for the kit there's a link to a
zip file which contains 5 example programs showing how to use the different parts of the robot kit.
Could you please try downloading the zip file and running the ultrasonic sample? When you run it and then look at the serial output from the robot you should see it returning the measured distance.
Regards
Alan