I just updated Mac OS to 10.5.4, but when Software Update installed the update, it just hung at about 30%. I pressed the power button after a while and got the offline installer to do a manual install.
So if you are having problems with the latest update, just download it from the Apple website and install it manually.
I am having problem installing a Security update. It asks to restart and when i Restart it hangs at configuring Installation.