I tried it with the serial port and didn't help, I just removed the OP cable to check it for continuity. The error states OP Cable so going through every possible cable and reseating them and blowing them out.I have the newer 2 color unit. Is the error happening when you're trying to view the files on a USB drive? If so, try plugging your computer directly into the serial port to see if that bypasses the issue. This is just a guess based on the name of the error...