So I'm trying to import a .PAT pattern file I downloaded from into Illustrator CS3 and can't find information on how to make it work. I've tried copying the PAT file into the Pattern directory in the Program Files and I can see the new option in the Swatch Libraries Menu > Patterns, but it is listed with the file extension and doesn't work when I select it, saying that it is an unknown format.

So how do you get a .PAT file into Illustrator and actually use it?