You're clicking on the wrong link to download. When you go to mirror creator, wait a while for the entire page to load. You'll see a list of download sites near the bottom of the page.
It's an intentional trick by MC to make you click on iLivid and download. You don't need that at all.
Once the links appear, just click on your favorite file sharing service link, a new window will open, and the link will be on that page. Click on the link on that new page and the actual sharing service page will appear with the download link (and another annoying ad will pop open behind everything).
I'm on a Mac and I download from these links all the time, no problem.
It's a lot of trouble (all the pages opening) but hey, the price is right :-)
you will get the download links for the file. Just click the mp4 high quality download. For those who don't know how to get video downloads from Youtube.