No declaration for attribute xmlns:html of element book

["Mike Devlin" <mike_devlin@fastmail.fm>]

Hi

I hope someone can help. I can't seem to work out why I'm having
trouble:

When validating my document I get these errors (and others that are
related)

validating doc100.xml:
doc100.xml:11: validity error: No declaration for attribute xmlns:html
of element book
      xmlns:xlink="http://www.w3.org/1999/xlink";>
                                                ^
doc100.xml:11: validity error: No declaration for attribute xmlns:xlink
of element book
      xmlns:xlink="http://www.w3.org/1999/xlink";>
                                                ^
My XML Document looks like this

<?xml version = "1.0" encoding = "iso-8859-1"?>
<?xml-stylesheet  type="text/css" href="mycss.css"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
"docbookx.dtd" []>
<book lang = "en_GB" conformance="2.0"
      xmlns:html="http://www.w3.org/1999/xhtml";
      xmlns:xlink="http://www.w3.org/1999/xlink";>

 <html:a name="book"/>                
 <html:script src="../toc/mtoc.js"/>
 <html:div style="text-align:right;"><!--some jiggery-pokery in
 here--></html:div>

   <bookinfo>...</bookinfo>
...
</book>

I want to include the html elements to aid my use of CSS. I thought
declaring the namespaces would do the trick but I don't seem to be going
about it in the right way.

BTW. If I got this working, would I screw up the XSL transformations?

Cheers

MikeD
-- 
  Mike Devlin
  mike_devlin@fastmail.fm