XML : No declaration found for element

I have a simple xml and xsd files. I am using xerces to generate .h/cpp files but when I run the application it gives an error:

no declaration found for element 'x:books'

My XML file is:

  <?xml version="1.0"?>  <x:books xmlns:x="urn:books"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xsi:schemaLocation="urn:BookStore books.xsd">       <book id="bk001">        <author>Writer</author>        <title>The First Book</title>        <genre>Fiction</genre>        <price>44.95</price>        <pub_date>2000-10-01</pub_date>        <review>An amazing story of nothing.</review>     </book>       <book id="bk002">        <author>Poet</author>        <title>The Poet's First Poem</title>        <genre>Poem</genre>        <price>24.95</price>        <pub_date>2001-10-01</pub_date>        <review>Least poetic poems.</review>     </book>  </x:books>    

and xsd file is:

  <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"              targetNamespace="urn:BookStore"              xmlns:bks="urn:BookStore">      <xsd:element name="books" type="bks:BooksForm"/>      <xsd:complexType name="BooksForm">      <xsd:sequence>        <xsd:element name="book"                     type="bks:BookForm"                     minOccurs="0"                     maxOccurs="unbounded"/>        </xsd:sequence>    </xsd:complexType>      <xsd:complexType name="BookForm">      <xsd:sequence>        <xsd:element name="author"   type="xsd:string"/>        <xsd:element name="title"    type="xsd:string"/>        <xsd:element name="genre"    type="xsd:string"/>        <xsd:element name="price"    type="xsd:float" />        <xsd:element name="pub_date" type="xsd:date" />        <xsd:element name="review"   type="xsd:string"/>      </xsd:sequence>      <xsd:attribute name="id"   type="xsd:string"/>    </xsd:complexType>  </xsd:schema>    

I have done a simpler demo with xerces but this one using namespaces and I think that seems to causing but but I don't know how..I am new to xml.