Looking at a picture of your front panel doesn't help anything. We can't see your actual code. You should attach the actual VI so we can see the code, and even those settings that may not show up on a picture of the block diagram. You haven't mentioned what device you are talking to. What is this "control box"?
This error has come up thousands of times before. Search the forums and you'll find numerous messages that could help you figure out what is wrong. Assuming the cable is correct, and the serial port settings are correct, the most likely scenarios are you didn't send the correct command to the device and so it is not responding or you didn't set up termination characters properly.
