NikonScan: Leopard vs Snow Leopard
I had been having problems running NikonScan with my 4000ED and Leopard on an iMac. Frequently, I'd have to do a restart to get the main window to appear. So, I upgraded to Snow Leopard, thinking things could hardly get worse. Much to my surprise and delight, NikonScan appears now to be completely stable (he says, fingers crossed.)
If you're having a similar problem, you might consider an upgrade; it's cheap at $29 and easy to install.