I used to work in a sewing factory, and once in awhile we would have the same trouble on the Mitsubishis. Most of the time we just had to make a minor adjustment.
I don't know if your machine is like mine, but mine has 2 tension knobs. the main one that you use to fix your top tension, and a smaller one before that. Turn the smaller one looser one whole turn. try your cutter for a bit, if that doesn't work, turn a little looser again. Keep your eye on your tension though. Shouldn't cause a problem with just a 2 or 3 turns of the smaller knob.
Here is a pic of my machine with the smaller knob circled. remember "Lefty Loosey Righty Tighty" :)