Ben, what's good about XHTML 1.1?
XHTML is XML-HTML rather than SGML, and is stricter than HTML
4.01 (which Paul is using, or at least trying to.) XHTML 1.1 isn't particularly better than 1.0 Strict (except for the modularisation), but XHTML is generally better than HTML 4.01. See varying and many W3C information pages on this subject.
Paul - upload your site, and post the URL.