To throw in my 2 cents; I don't use the script (although it does work in OS X). I much prefer to use the built-in OS X app called Grab. You have the options of capturing an individual window or dialog box, the whole screen, a timed screen shot or you can make a selection. If a person wants to get "fancy", an Automator script can be used to name and place screen shot in a particular folder. I no longer go to that length, but I use Grab with every project to capture MoI model views and then bring them into PhotoShop to quickly place them on a uniform background.