Error 2053

<?xml version="1.0"?>

http://www.w3.org/2003/05/soap-envelope">

<env:Body>

<env:Fault>

<env:Code>

<env:Value>env:Receiver</env:Value>

<env:Subcode>

<env:Value>-2053</env:Value>

</env:Subcode>

</env:Code>

<env:Reason>

<env:Text xml:lang="en">Could not Generate XML Schema</env:Text>

</env:Reason>

<env:Detail>

<Object>oDocuments</Object>

<Object>oDocuments</Object>

<ObjectIndex>1</ObjectIndex>

<Command>AddObject</Command>

<SessionID>2789C3B9-2E34-EC45-4F44-9E5F224CF30D</SessionID>

</env:Detail>

</env:Fault>

</env:Body>

</env:Envelope>

when I add an order ,that's the error ,who know the reason