XmlValidatingRe ader gives me an error

[Sangeetha Nagaraj]

Hi,
I am writing a program to validate a XML file and i am getting an error.
Here is my Code, and i get an error at "args.Exception "

("The 'urn:books:cata log' element is not declared. An error occurred
at file:///c:/inetpub/wwwroot/LakisService/books.xml, (2, 2).")

private void Button2_Click(o bject sender, System.EventArg s e) {
XmlTextReader r = new XmlTextReader(S erver.MapPath(" books.xml"));
XmlSchema xs = new XmlSchema();
xs.SourceUri = Server.MapPath( "books.xsd" );

XmlValidatingRe ader v = new XmlValidatingRe ader(r);
v.Schemas.Add(x s);
v.ValidationTyp e = ValidationType. Schema;
v.ValidationEve ntHandler += new ValidationEvent Handler(MyValid ation);
while (v.Read()){
}
v.Close();
}

public static void MyValidation(ob ject sender, ValidationEvent Args
args){
string strErr="";
if (args.Exception != null){
strErr = args.Message;
}
}

XML FILE
--------------
<?xml version="1.0" encoding="utf-8" ?>
<x:catalog xmlns:x="urn:bo oks">
<book id="bk101">
<author>Gambard ella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer </genre>
<price>44.95</price>
<publish_date>2 000-10-01</publish_date>
<description> An in-depth look at creating applications with
XML.</description>
</book>
</x:catalog>

XSD FILE
---------------
<xsd:schema xmlns:xsd="http ://www.w3.org/2001/XMLSchema">
<xsd:element name="catalog">
<xsd:complexTyp e>
<xsd:sequence >
<xsd:element name="book" minOccurs="0" maxOccurs="unbo unded">
<xsd:complexTyp e>
<xsd:sequence >
<xsd:element name="author" type="xsd:strin g" />
<xsd:element name="title" type="xsd:strin g" />
<xsd:element name="genre" type="xsd:strin g" />
<xsd:element name="price" type="xsd:float " />
<xsd:element name="publish_d ate" type="xsd:date" />
<xsd:element name="descripti on" type="xsd:strin g" />
</xsd:sequence>
<xsd:attribut e name="id" type="xsd:strin g" />
</xsd:complexType >
</xsd:element>
</xsd:sequence>
</xsd:complexType >
</xsd:element>
</xsd:schema>

Give me your suggestions to solve this,,,

--
Rgds,
Sang