I feel your pain. It's happening to me (not upgraded to Snow Leopard yet) with the brush, patch, eraser, etc.
I called Adobe and they referred me to the adobe site and gave me a document id to search for there. It didn't come up on the search, so now I've replied to them and waiting to see if I misheard the document name.
I'll post a link here when I get it from them.
Well, this may be helpful...or may not.
The info Adobe gave me was sort of generic (run disk utility, toss prefs, etc.). I did most of what was listed, but I wasn't optimistic and sure enough no effect.
Yet, miraculously, now I'm good! All that I did was restart my Mac and let the latest OS update install. I can't say with 100% certainty that that is the fix, but none of the other things worked. Hope it sticks!