Issue playing Vimeo in IE using WordPress 3.6

There appears to be an issue with playing Vimeo videos trough the use of iframes in WordPress 3.6 using Internet Explorer (tested version 10,9, and 8). The videos play fine on the latest versions of Safari, Chrome and Firefox.
Has anybody come across this issue and how to fix it?
The website the videos should run on is:
http://www.richmondwestps.vic.edu.au

But I also encountered the problem on other sites, like:
http://www.wp101.com/tag/wordpress-3-6/

Any suggestions to fix this would be appreciated!