HTML5 website bug in IE7 only

Need some help figuring out why the car scroller section of this page (http://www.penskemercedesinfo.com/) appears out of place on IE7 only. Appears fine on latest versions of FF, Safari, Chrome and IE8.

Is it my CSS or an HTML5 bug? I'm using a trimmed down version of HTML5 Boilerplate modified for Wordpress.

Check http://www.quirksmode.org/dom/html5.html and http://caniuse.com/ to see the compatibility of HTML5 in various browsers.

I've checked those. Gotta be something else.

Worth checking through your validation errors (http://validator.w3.org/check?uri=http%3A%2F%2Fwww.penskemercedesinfo.com%2F&charset=%28detect+automatically%29&doctype=Inline&group=0) - there seem to be a few unclosed tags in there which could be causing the problem.