Have you tried operating the camera with no film in it? Open the back and see what is going on. As you wind on, the take up spool should turn as well the advance. See if things spin freely when you push the rewind button on the bottom of the camera. The only other thing I can think of to check would be how tightly the film is wound in the cassette, or if the rewind knob is binding, needing extra effort to advance the film.
Overall, they're pretty simple cameras and if something has gone wrong it shouldn't be too major a problem.