Wordpress header in Opencart issue PLEASE HELP!

Can anyone tell me what its causing my site to break in IE9? I copied the WordPress header source code into the header of the Opencart header.tpl and all is well in Firefox & Chrome. In IE however...If you enter the product page through the categories on the left the product page left aligns...I can't figure this out for the life of me.

Can anyone PLEASE help me on this?!!! My site is http://www.sterlingportable.com/store/

Im on a Mac But it works on Safari. Others will help

Ya it seems to be only Internet Explorer. Thanks for looking though. I really hope someone can help me because I just can't figure this on out! Come on guys, some one out there has to be able to figure this out. PLEASE!