The link in the thread for the Mac version (which is in beta and I guess was abandoned) 404s. Can someone point me to a download for the latest version of the Mac version of the AGS runtime?
A Google search (http://www.google.com/search?gcx=c&sourceid=chrome&ie=UTF-8&q=AGS271beta3b.dmg) turns up some results which may work. I believe the Mac version is discontinued, though.
Some info from the guy that bothered with the MAC port in the first place. (http://www.adventuregamestudio.co.uk/yabb/index.php?topic=30021.msg565855#msg565855%5B/url)
This probably answers your question.