Can't expand additional codecs

Added by John Etnier almost 2 years ago

The Mplayers OSX Extended site says:
"MPlayer Binary Codec Package (x86/PCC)
Download from MPlayer.
Installing the binary codec pack for your architecture will add support for additional proprietary codecs"

I have downloaded the zip file (essential-macosx-x86-20060611.zip) from the linked page, but it won't expand: Error -1 Operation not permitted.

Anyone know how to work around this?