I use Safari on my MacBook and initially it wouldn't open. I'd get this message: "Please wait...If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document." I also got the same message with Google Chrome. It worked fine using Internet Explorer though.
If you're using Safari: once the "please wait" page opens, click the icon on the right of the zoom out button below (it looks like 2 sticky notes with a tac) and it should open. (You can only see the zoom icon when your cursor is at the bottom)