Okay... I've been trying to figure this out for awhile. I kept getting a memory error when trying to do things like Open a file in Photoshop CS3, or if I opened it directly (right-clicked on a pic and told it to open with Photoshop) I could get a pic in but if I tried to Save or Save As... it would CRASH. It would just say that the Application quit unexpectedly. Anyway... I've been looking for an answer to this and some said it was permissions problems... tried uninstalling-reinstalling but no luck. I'm on a MBP 1.1 (2 GHz, 2 GB Ram, Intel) running Leopard (which I upgraded from Tiger).
Here's the solution that worked for me:
This fixes a corrupted Version Cue update that apparently gets called when doing anything major with a lot of CS3 products. I ran this file and Voila! I can open up files! Hope this helps out somebody else that has been suffering through this fun, fun time with CS3.