Apparently the developer is having some issues with the links on the site. However when you get the 404 error you are on the developers site. From there you can still click on the 68 Classifieds link as well as the modules link with all the available modules offered from the developer for download.
You don't need it. Just go to twitterfeed.com It's really easy but if you get stuck just let me know in this thread. Good luck.