I can't get it to work either. When I click on the download button it opens the thank you for downloading message, but for some reason it doesn't start the download. I tried reloading the page and clicking on the button several times, but it just won't download.
Strange! You can try one of these direct links:
https://dl.dropboxusercontent.com/u/18560757/Water... (OS X)
https://dl.dropboxusercontent.com/u/18560757/Water... (Win)
Let me know if neither of these works.