This site has never been tested on a Mac during development. [I
don't own one!]
But, the site does have 2 interfaces - a nice one for the majority of
users [AOL, Window's Internet Explorer 5.x and better] and one 'not
so nice one' which should work for everyone else.
So could you provide me some more detail about which browser you
are using on your Mac. Also, when you go to the board view, do you
see radio buttons [peg holes] on every tile?