JAXBException while unmarshalling an xml file

[Sikku]

Hi all,
Im trying to unmarshall an xml file which i have in the form of a
StringReader. When i try to unmarshall it by calling the following
unmarshall method

Envelope env = (Envelope) unmarshaller.unmarshal(new
StreamSource(xmlReader));
its throwing a JAXBException

[12/9/06 15:25:41:859 GMT] 39eb6d00 SystemOut O
DefaultValidationEventHandler: [ERROR]: uncompleted content model.
expecting: <Response>
[12/9/06 15:25:41:219 GMT] 236dad00 SystemErr R
com.sun.msv.verifier.ValidityViolation: uncompleted content model.
expecting: <Response>

can anyone please suggest what might be the possible solution for this
problem.


Thanks in advance.....