Problems with IE displaying html5

[nitsud08]

Hello. This is my first post and am very happy to be part of your community!!! I created a site for a client at www.vacationocg.com It is not being displayed at all in older versions of IE. I am assuming this is because it is html5 but I am not certain. All it does is load the background color and freezes up. I found a fix at http://www.designerkawch.com/337/html5-enabling-script/ and copied the script into the header.php file (i am using WordPress) but it still freezes up. It gets a little bit further in the page load when I add that script, but not all the way. I am a student and still learning of course. Just wondering if anyone had any other potential solutions for this. thanks so much!