Brush Errors!?!?!

Hey guys, the problem seems to happen when I fool around with my projects layers (turning turning them on and off) all my tools lock up and when i try to click back onto my work.

I get this error "Could not use the brush tool because of a program error"

Then I need to save my work and restart PS to work on it another 5 mins before it locks up again.

Im using a wacom tablet w/ newest drivers.

Thanks in advanced for any help.

What version of PS and what types of brushes and settings? Some image based brushes with transparency show odd behaviors with pressure sensitivity and such, so more info would certainly help.

Mylenium