Sculpting mode... bug, improper use on my part? Need help

I’ve been watching tutorials on Blender for some time to try and figure out how to sculpt, and what I do on my screen is not what happens when the person in the tutorial flies through sculpting. I don’t know if I left something checked that I shouldn’t have, or if there is a bug, or what.

When I initiate sculpting mode and select Brush, then try to sculpt the vertexes that I’m looking at, very little if anything happens. If I keep playing the brush back and forth, every once in awhile a few vertexes will move, but only those near the middle of the block. Sometimes the cursor stops moving. Essentially, I can’t really do anything. I have no idea what to try next.

I have used ‘f’ to change the feather, and I’ve tried many different types of ways to sculpt, brush, clay, and so on, none of which particularly do anything. I’m running Blender 2.68. I would really appreciate an answer to what I’m doing wrong, or some explanation as to how its actually supposed to work. It looks quite easy in the tutorial, but nothing is happening on my computer.

Have you given the brush a large enough strength
Have you masked your mesh ?
What is the scale of your object ? Is it different to 1 ?

Post a link to an example blend file that shows the problem

Might be a symptom of not subdividing the mesh (in the multires modifier panel) enough times.