Can't use multires sculpting layer tool to make raised circular spots.

I am trying to do a tutorial from here: http://cgcookie.com/blender/2010/07/15/a-stylized-dragon-part-5/. I’m at the part where I am supposed to use multires sculpting layer tool to make raised circular spots on the dragon. I’m using a newer version of Blender so some of the options are different. I can’t get my circular patterns to look clean cut as shown in the tutorial. Can someone tell me how to do this?

This is how the circles look in the tutorial:
http://i1130.photobucket.com/albums/m539/Blanco111/Works%20in%20Progress/th_help9.png

This is the best I am able to make (even with my pressure tablet):
http://i1130.photobucket.com/albums/m539/Blanco111/Works%20in%20Progress/th_help8.png

For some reason the Blender file got very large (180MB) I’m thinking it’s the Multires modifier, but I don’t know. I converted a smaller backup blender file and uploaded it to the site below. I couldn’t upload it here for some reason. I got an error message. This the first time I’m using the pasteall.org site, so I don’t know if it will work, etc.

http://www.pasteall.org/blend/18324