RS232 Port Errors on Windows 7

We are trying to hook up a Hanwa ESD Simulator to a Windows 7 machine. on the Hanwa GUI, when we click on 'Start Test', we are getting the following error.

1. We changed RS232 cable: Error persists
2. We verified that the ESD Simulator was turned on and connected.
3. We configured the port in the Device manager.

4. We re-installed all driver software: issue still persists.
5. We tried different ports: issue still persists.

Do you know how we can solve this error?