Hi-
I'm trying to create a favicon, but when I attempt to install the plugin for Photoshop (e.g., from Telegraphics http://www.telegraphics.com.au/sw/icoformat.en.html), Photoshop says that it couldn't open because it doesn't recognize it. Any idea on what I'm doing wrong? Thanks!

Background
Adobe Creative Suite 5
Mac, Intel, OSX 10.8.2, 2.53 GHz Intel Core 2 Duo, 4 GB 1067 MHz DDR3