Firefox not displaying embedded youtube iframe within ajax loaded post, working in all other browsers

I am developing a website with WordPress and just working on the video embedding. It works with Vimeo in all browsers, and Youtube in all browsers except Firefox. It works in the single post view, but not when the posts are loaded with ajax on the main page.

I am running Firefox 10.0.2 in Windows 7 64

Any ideas why this isn’t working?

EDIT: the dev site is gone, but the final website is at http://epicvan.com
In the final version of the website, since a solution was never found, we just eliminated YouTube embedding entirely.