I had a similar problem about a week and a half ago with the Superskimmer 65. Mine was used, so I didn't have to break it in (which can take a few days/weeks). My cup would fill up in about 10 to 15 minutes because the air intake on the pump was mostly clogged. Once I cleaned it out, it worked just fine. Check the intake, air line and silencer (if you're using it). Also, how deep is your pump? It should be 2" to 3" inches below the surface of the water (the closer to the surface, the better).
Something to keep in mind with these skimmers is that they are sensitive to water level changes. You've got to keep the tank topped off, or you will not be getting an efficient skim. Also, once you get it going, don't be worried of it produces a lot of microbubbles. They will pretty much go away after a few days (unless it's a new skimmer, in which case it could take a week or two).
Once you get everything working, open the valve so the bubbles are near the bottom of the cup then make as small of an adjustment as you can then let it run for an hour or so. Continue raising the bubble level until you get the kind of skimmate you desire. It takes time, but it's worth it. Superskimmers are skim well, once they have been fine tuned.