It's a Chrome issue (well actually it's an SSL issue that Chrome is rightly obeying - we're looking at it.
We are still looking into where these files are referenced over http instead of https, but in the meantime there is a workaround.
Workaround 1: In Chrome, when you load the forum page, in the address bar there is a little shield on the right hand side. Click this and it will tell you there is insecure content. If you want, you can press "load anyway" - it should remember it for this site, and then display a red https with a line through it on the left hand side.
Workaround 2: Use another browser. (Firefox, Internet Explorer, Safari.)