I see, you’re serving what’s called mixed content.
You have a link on your site to http://upload.wikimedia.org/wikipedia/commons/thumb/3/30/RedDisc.svg/20px-RedDisc.svg.png. As you can see, this is looking at a http:// link and not a https:// link. If you change this (and any other instances of http:// links) then your error will go away 