Frost buildup in ice dispenser

We have a Kenmore Cold Spot 59592990 side by side refrigerator/freezer. It's been extremely ok. Much of the workmanship is disappointing, but it has met our needs. Recently, the ice dispenser has been causing problems. The bottom of the freezer-part-dispenser (the part that feeds the ice to the door-part-dispenser) gets a coating of frost (thick-type frost), as does the top of the door-part-dispenser. The frost accumulates inside the freezer (door-part) dispenser to the point where it blocks ice from being dispensed. Then we open up the door and the blocked ice spills all over the place. As far as we can tell, the freezer door closes properly, and we're not seeing any obvious gaps in the dispenser tube/flap (obviously, I'm not a real technical person when it comes to refrigerators, so I hope I'm painting a clear enough picture). Do we need a repair person, or is there something we can try ourselves? Thanks very much.