Is this a flat floor slide, one that has to rise up before beginning its inward travel? Failure to rise up enough could chip the front edge as it bumps up over the main floor. If it is one that stays above the main floor, i.e. has a 2 inch step up onto the slide floor, I would suspect nail or screws protruding on the underside, either from the bottom of the slide floor or the top of the main floor.
There are several different slide mechanisms, both rack & pinion and hydraulic, so it is difficult to say what adjustments should be made to yours. I would be inclined to have a dealer or the factory diagnose and repair it. Otherwise, it is probably a matter of trial and error. And if you loosen the wrong thing, it could get severely out of kilter and need to be jacked up to get it back on track.