So it turns out lowpro is broken in the latest Firefox. Anyways DanWebb has released a fix for this which you can read more about here.

Now this didn't solve my issues all together. I ran into an issue as the JavaScript was loading before the page was completely loading and thus the behaviours were not been added.

So the solution is to add the following

Event.observe(window, 'load', function() {
    // assign behaviors

That way the behaviours don't get added until after the DOM has fully loaded.