As a newbie to PP, I don't know much about it but I did notice something as I was ripping paper last night, which might be helpful if people are having trouble with copy paper.
I use a bigger needle, the 1.5 stitch setting, and when I rip out the paper, I do it carefully, the way I would rip a check out of my checkbook. fold it up on the perforation, then unfold and tear carefully, pulling away from the perforation, not ripping it upward. Once one side of the perforated paper is torn off at the perforation line, the other side comes right off, and there is no upward stress on the stitches to pull them loose.