Schema Validation Issues

Hey all. On seeing the new DOM XML/XSLT/XPath et al integration with PHP5 I
thought - finally!

However, that didn't last too long :)

I'm almost certain this isn't an issue with the new systems ... more likely
an issue with my old brain ... but thought I'd head to the source for any
advice/pointers/flamings as required.

Anyway .. enough rambling ... the issue:

I have an xml schema and an xml sample file that should validate against the
schema.

I get the error 'Invalid Schema' and I was pretty sure the schema was right
...

To double-check I used an old example schema (from on of the Visual
Quickstart Guides I picked up 5 years ago) thinking this should work - it
did before :)

I Ran the schema across it's own sample xml file and got same error.

I then ran the schema against the wc3 schema validation service and it
'seems' to validate?

Pasted below is the schema file and the xml file being validated. What have
I missed here? Anyone?

----- SCHEMA FILE -----
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2000/10/XMLSchema">

<xsd:element name="endangered_species" type="endspeciesType"/>

<xsd:complexType name="endspeciesType">
 <xsd:sequence>
  <xsd:element name="animal" type="animalType" maxOccurs="unbounded"/>
 </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="animalType">
 <xsd:sequence>
  <xsd:element ref="name" minOccurs="1" maxOccurs="unbounded"/>
  <xsd:element name="threats" type="threatsType"/>
  <xsd:element name="weight" type="xsd:string" minOccurs="0"/>
  <xsd:element name="length" type="xsd:string" minOccurs="0"/>
  <xsd:element ref="source"/>
  <xsd:element name="picture" type="pictureType"/>
  <xsd:element name="subspecies" type="subspeciesType" minOccurs="1"
maxOccurs="unbounded"/>
 </xsd:sequence>
</xsd:complexType>

<!--Here are the global declarations of the name and source elements. Notice
that they are considerably simplified for this example. -->
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="source" type="xsd:string"/>

<xsd:complexType name="threatsType">
 <xsd:sequence>
  <xsd:element name="threat" type="xsd:string" maxOccurs="unbounded"/>
 </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="pictureType">
 <xsd:complexContent>
  <xsd:restriction base="xsd:anyType">
  <xsd:attribute name="filename" type="xsd:uriReference" use="required"/>
  <xsd:attribute name="x" type="xsd:integer"/>
  <xsd:attribute name="y" type="xsd:integer"/>
  </xsd:restriction>
 </xsd:complexContent>
</xsd:complexType>

<xsd:complexType name="subspeciesType">
 <xsd:sequence>
  <xsd:element ref="name" minOccurs="1" maxOccurs="unbounded"/>
  <xsd:element name="region" type="xsd:string"/>
  <xsd:element name="population">
   <xsd:complexType>
    <xsd:simpleContent>
     <xsd:extension base="xsd:nonNegativeInteger">
      <xsd:attribute name="year" type="xsd:year"/>
     </xsd:extension>
    </xsd:simpleContent>
   </xsd:complexType>
  </xsd:element>
 </xsd:sequence>
</xsd:complexType>

</xsd:schema>
---- END ---

--- XML file ---

<?xml version="1.0"?>
<endangered_species xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="http://www.cookwood.com/xml/examples/namespac
es/global_endspecies.xsd">
<animal>
 <name>Tiger</name>
 <name>panthera tigris</name>
 <threats><threat>poachers</threat>
 <threat>habitat destruction</threat>
 <threat>trade in tiger bones for traditional Chinese medicine
(TCM)</threat>
 </threats>
 <weight>500 pounds</weight>
 <length>3 yards from nose to tail</length>
 <source>World Wildlife Fund</source>
 <picture filename="tiger.jpg" x="200" y="197"/>

 <subspecies>
  <name>Amur or Siberian</name>
  <name>P.t. altaica</name>
  <region>Far East Russia</region>
  <population year="1999">445</population>
  </subspecies>

 <subspecies>
  <name>Balian</name>
  <name>P.t. balica</name>
  <region>Bali</region>
  <population year="1937">0</population>
 </subspecies>

 <subspecies>
  <name>Javan</name>
  <name>P.t. sondaica</name>
  <region>Java</region>
  <population year="1972">0</population>
 </subspecies>

 <subspecies>
  <name>Caspian</name>
  <name>P.t. virgata</name>
  <region>Caspian Sea</region>
  <population year="1950">0</population>
 </subspecies>
 <subspecies>
  <name>Bengal</name>
  <name>P.t. tigris</name>
  <region>India</region>
  <population year="1999">3159</population>
  </subspecies>

 <subspecies>
  <name>Sumatran</name>
  <name>P.t. sumatrae</name>
  <region>India, Bangladesh</region>
  <population year="1999">400</population>
  </subspecies>

 <subspecies>
  <name>Amoy</name>
  <name>P.t. amoyensis</name>
  <region>South China</region>
  <population year="1999">20</population>
 </subspecies>
 <subspecies>
  <name>Indo-chinese</name>
  <name>P.t. corbetti</name>
  <region>Indo-China</region>
  <population year="1998">1227</population>
  </subspecies>
 </animal>
<animal>

 <name>Black Rhino</name>
 <name>diceros bicornis</name>
 <threats><threat>poaching to satisfy demand for rhino horn in traditional
Asian medicines and as decorative dagger handles in Middle East</threat>
 <threat>habitat destruction</threat>
 </threats>
 <source>World Wildlife Fund</source>
 <picture filename="rhino.jpg" x="200" y="158"/>
 <subspecies>
  <name>Southern Black Rhino</name>
  <name>D.b. minor</name>
  <region>Zimbabwe and South Africa</region>
  <population year="1999">1365</population>
  </subspecies>
 <subspecies>
  <name>Southwestern Black Rhino</name>
  <name>D.b. bicornis</name>
  <region>Namibia</region>
  <population year="1999">740</population>
  </subspecies>
 <subspecies>
  <name>Eastern Black Rhino</name>
  <name>D.b. michaeli</name>
  <region>Kenya (Ethiopia and Rwanda)</region>
  <population year="1999">485</population>
  </subspecies>
 <subspecies>
  <name>Northwestern Black Rhino</name>
  <name>D.b. longipes</name>
  <region>Cameroon</region>
  <population year="1999">10</population>
  </subspecies>
  </animal>
 </endangered_species>

---- END ---