I've been using CS4 on my macbook pro, I have Alien Skin plug ins that I use quite a bit. Recently, after using the Alien Skin actions, CS4 shuts down if I try to use them a second time. So, I open a photo, use the Alien Skin, continue to edit, but if I decide to use Alien Skin again, it shuts down CS4. Anyone know why this is the case? It didn't do this previously, just started in the last couple of days.
Have you tried recreating the Photoshop preferences? (Hold down Ctrl+Alt+Shift on Win or Command+Option+Shift on Mac during startup of Photoshop).
If that doesn't work, I'd suggest uninstalling and reinstalling Alien Skin.