The Mac OS X 10.5.6 update broke pwnage, the unlocking/jailbreaking program for the iPhone. Fortunately, there's now an easy solution to fix this problem. You just need an Automator script and these simple instructions.
You first need to be logged into the Mac with administrator privileges and, when asked, you have to provide with the administrator password.
Yes, it's that easy. Enjoy. [Get the script here or here via Hackintosh]