whether the page display correctly or not isn't anything important if you really want to validate your website..

validating a website means that you're using correct code..means it's standards compliant.

most websites can't validate but display properly and that's not what people are aiming for if they're planning to validate their website.

You forgot to close your DIV tag for the Class property "centerbox"?

it'll be less headache if we could see the code.. but you can try closing the open DIV first.