[XML Schema] file non valido, ma perchè??

[alyas4]

Questo è lo schema ( mi sembra banale e semplice...)

<?xml version="1.0" encoding="UTF-8"?> 
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:thunt="http://vitali.web.cs.unbo.it/thunt" targetNamespace="http://vitali.web.cs.unbo.it/thunt" elementFormDefault="qualified">
<xs:element name="sendSubscriptionResult">
  <xs:complexType mixed="true">
    <xs:attribute name="status" use="required">
    <xs:simpleType> 	
      <xs:restriction base="xs:token">
        <xs:enumeration value="accepted"/>
        <xs:enumeration value="passAlreadyAssigned"/>
        <xs:enumeration value="notExist"/>
        <xs:enumeration value="noPermission"/>
        <xs:enumeration value="alreadySubscribed"/>
      </xs:restriction>
    </xs:simpleType>
    </xs:attribute>
  </xs:complexType>
</xs:element>
</xs:schema>

e questo è il file (ancora più semplice)

<?xml version="1.0" encoding="UTF-8"?>
<thunt:sendSubscriptionResult status="accepted" xsi:schemaLocation="http://vitali.web.cs.unibo.it/thunt 32.xsd" xmlns:thunt="http://vitali.web.cs.unibo.it/thunt" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>

e l'errore avviene utilizzando la schemaValidate() in php5:

Warning: DOMDocument::schemaValidate() [function.DOMDocument-schemaValidate]: Element '{http://vitali.web.cs.unibo.it/thunt}sendSubscriptionResult': No matching global declaration available for the validation root.

ma validandolo con un altro software non da errori...
Dove è la fregatura?