Validation of Docbook 5.0 XML via XSD with C# .Net

I try to validate a docbook 5.0 xml via c# and xsd data.

I started from the example here: http://ift.tt/1n92dbt where it is pretty easy and simple. I made the notValidXSD.xml (in the example) valid removing the first book caling it nowValidXSD.xml and it words fine.

Now i tried the same for the Docbook 5.0 format ( docbook.xsd, xml.xsd xlink.xml ) which you can download here http://ift.tt/1n92afF

Trying the code ( given by the example on msdn above) gives me :

Validating XML file mydocxml.xml
Validation error: the http ://www.w3.org/XML/1998/namespace:id-Attribute is not declared.
Validation error: the http ://docbook.org/ns/docbook:article-Element  is not declared.
Validation error: the schema informationen für das Attribute 'version' could not be found.
Validation error: the http://ift.tt/1n92dbv is not declared.
Validation error: the  http://ift.tt/1n92dbx is not declared.
Validation finished. Validation failed.

( i hat to make spaces after http becouse its my first question here ) I dont know what to do anymore. For me the files look fine. I tried googling the problem for hours now and cant seeem to be able to validate via c#.

Here are the files:

<!-- nowValidXSD.xml -->
<?xml version='1.0' encoding="UTF-8"?> 
<bookstore xmlns="urn:bookstore-schema"
     xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="urn:bookstore-schema books.xsd">
  <book genre="novel">
    <title>The Confidence Man</title>
    <author>
      <first-name>Herman</first-name>
      <last-name>Melville</last-name>
    </author>
    <price>11.99</price>
  </book>
</bookstore>

And the docbook xml

<!--  mydocxml.xml -->
<?xml version="1.0"  encoding="UTF-8"?>   <!--   -->

<article xmlns="http ://docbook.org/ns/docbook" version="5.0"
   xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http ://docbook.org/ns/docbook docbook.xsd">
  <title>some title</title>
  <para> some text.</para>
</article>