Blender 2.5 Sculpt problems

Hello everyone!

I have been doing some tutorials that require me to go into sculpt mode, but I’ve been having soem problems when working with this mode. Perhaps the biggest problem is that I cannot undo while in Sculpt Mode. It crashes the program. I also could not use the Smooth tool. The tutorial was doing used a lot of the grad tool. It worked for a while, but after a certain point, it would grab points, but not move them. I quit the tutorial and worked on my own project, testing the sculpt tools, and it did the same thing again. Does anyone have any ideas as to what the problem is?

I am using a Macbook Pro, running Mac OS X 10.6.4 with a 2.8 GHz Intel Core 2 Duo. I am also using my Wacom Intuous 4 tablet mouse. If you need any more information let me know.