Some of those errors shouldn’t be there. For example,
Line 168, Column 6: end tag for element “HTML” which is not open.
</html>
✉
The Validator found an end tag for the above element, but that element is not currently open. This is often caused by a leftover end tag from an element that was removed during editing, or by an implicitly closed element (if you have an error related to an element being used where it is not allowed, this is almost certainly the case). In the latter case this error will disappear as soon as you fix the original problem.
The <html> tag is opened only once and closed only once.
Actually I just caught something else. Firefox doesn’t display the background image (the column of dots) and IE also doesn’t display the navigation menu. Any suggestions?
