How to Resolve SBL-ODU-01008 Error on Accessing CustomObject2 Web Service

Hi,

Please check how can i resolve the error below while accessing CustomObject2 webservice.

Error Results:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
      <soap:Fault>
         <faultcode>soap:Client</faultcode>
         <faultstring>Client</faultstring>
         <detail>
            <ErrorCode>SBL-ODU-01008</ErrorCode>
            <ErrorMessage>The HTTP request did not contain well-formed XML.  An attempt to parse it produced the following error: The prefix "cus" for element "cus:ListOfCustomObject2" is not bound.</ErrorMessage>
         </detail>
      </soap:Fault>
   </soap:Body>
</soap:Envelope>

Code:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:ns="urn:crmondemand/ws/customobject2/10/2004" xmlns:acc="urn:/crmondemand/xml/customobject2"