I've had the same problem. It's rather complicated to describe on-line but you need to adjust the outside wall of the slide downward, which will tip the inside part that's rubbing upward. You will find an adj. under the slide at each end. Adjust each side the same unless it is out of level front to back. Make a minimal adj. - maybe 1/4" and check your progress.
It would help to have a pic of the mechanism both inside (with the carpet lifted) and the outside area I described above.