Please explain validation error from Geier, Ronald - b.i.t.s. on 2010-08-12 (www-validator-css@w3.org from August 2010)

From: Geier, Ronald - b.i.t.s. <Ro.Geier@bits-gmbh.de>
Date: Thu, 12 Aug 2010 08:30:04 +0200
To: <www-validator-css@w3.org>
Message-ID: <40836C8770C2A440BABB55534687A5D40DD6BC1B@VSMUCEXCH11.mysug.de>

Hello,

i am not able to vaildate the css on the page: www.buchbohne.de xhtml
check is passed, css check always stops with:

CSS
Validator
Error
Target: http://www.buchbohne.de
Please, validate your XML document first!
Line 1
Column 3
The markup declarations contained or pointed to by the document type
declaration must be well-formed. 

What is wrong with the Declaration:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="de" xml:lang="de">


Thank you

Ronald Geier

Received on Thursday, 12 August 2010 16:21:40 UTC