[SOLVED] "class" appearing above header and navbar

Hi,

I am about to launch my site and discovered something strange - class appearing above header and navbar. For eg.:

class="single postid-4096">,
class="home blog">,
class="archive category category-architecture">

What could be causing this?
Using both latest WP 2.9.2
and ATA 3.4.6

I have black body background so could never see it but at the moment I have kept it white. Please have a look.
Thanks.

edit: Here is the link DesignFlute