Newbie question

Hi!

I was trying to use your validation service, but I just get the
following error message:

Error loading stylesheet: A network error occured loading an XSLT stylesheet:
http://www.w3.org/2000/06/style/xsv.xsl

What am I doing wrong? In this case, I uploaded a file with the
following contents (with some stuff deleted):

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
       xmlns="http://.../xsd/cdm/2010/08"
       targetNamespace="http://.../xsd/cdm/2010/08"
       elementFormDefault="qualified"
       attributeFormDefault="unqualified">
       <!-- type definitions -->
       <xs:complexType name="DurationType">
               <xs:sequence>
                       <xs:element name="StartDateTime" type="xs:dateTime"/>
                       <xs:element name="EndDateTime" type="xs:dateTime"/>
               </xs:sequence>
       </xs:complexType>
</xs:schema>

Thanks.