GMC Repair: Wiper Arm removal 2003 Buick Century, jaw puller, buick century

Question
2003 Buick Century
The passenger side wiper arm stopped working. I have removed the cap and nut but can't get the arm off. I am afraid of just using brute force.
The threaded shaft that the wiper arm fits over is rotating properly when the wipers are on but the arm remains stationary. Sometimes the arm will move a little ( a couple of inches) but it does not do this consistently.
What is the most likely problem and solution? How do I remove the wiper arm?  

Answer
You need to use brute force to remove it. Also you could get a battery terminal remover from your local auto supply store, it looks like a 2 jaw puller, and is what I have in my tool box for this. Also I would try manually moving the arm into it's proper place, and putting the nut back in and tightening it good. It is kind of normal for them to come loose on these cars from time to time, and tightening it normally fixes it. You could also put some locktite on the threads if this works.