I had a similar problem with my previous machine. My problem was with the rails that the machine traveled on. There were teeny-tiny nicks in the rails I couldn't feel with my hands that the machine wheels were catching on and not allowing it to move. I took very, very fine steel wool and sanded the entire length of the rails. That definitely helped a lot. If that doesn't help, I'd suggest loosen the rails and rotate them a half-turn, turning the offending area towards the floor so the machine doesn't run over that area on the rails.