my first suggestion is to try another post with "poll size not working" as the subject, because if someone has solved that with Flexi before, they will know to open your post. I don't use a Roland, but I use Flexi. I don't have much to offer though. For some reason the term "bi-directional communication" comes to mind, & I'm not sure if that even has relevance, or if it does, not sure if it is a setting in Flexi, or a type of cable. The software is sending data to the cutter ok, but the cutter sending data back is failing, so I guess that term may be applicable. does it have the option to be connected by sreial port? If so, do you have a serial port & a cable to test that for comparison? Or some other USB cables?