I try not to use tables ... as i enjoy CSS, and find it is simpler to work out lots of little issues. I took a look at your code, and couldn't really find my way around it, not could i find the problem. Good luck with it, yet from the site it looks like it will be changing pretty soon anyways.
Sorry i couldn't be of any help. The only thing that came to mind would be that if you are implementing the code fix so that it will work crossbrowsers. The grey band could be a result of a netscape issue.
I assume you are using IE, as the band appears for me, using IE.
Good Luck!