Error in IE "object doesnt support this property or method"

I am working on a new site and am getting the error “object doesnt support this property or method” in IE7. Menu works fine in all other browsers.



Example here:

hustlertube.com/hc/index.html

We have found only dhtmlxTabbar on the page ( the dhtmlxMenu  is not there ).

We have tested this page in IE6 and IE 7. In both browsers the issue doesn’t appear.