Think is my first post here, and since I'm new to Rolands, just bought a cx300, I had a grounding issue with other cutters. Make sure you attach a wire to one of the screws in the "body" of the cutter and another one to another screw on the stand.
Also, I don't know what software are you using (if any right now) but graphtecs have problems with the commands if you're cutting from flexi or illustrator if not set properly, HPGL from felxi and GPGL from Illustrator.
I'm probably wrong, but throwing a couple things out there, so the more experienced ones can elaborate more if any of my "theories" makes sense.
Hope you get this fixed man, it sucks to buy a brand name machine to fight it like if it were a chinese POS