I run onto the following exception a couple of days ago:

Caused by: org.w3c.dom.DOMException: NAMESPACE_ERR: An attempt is made to create
 or change an object in a way which is incorrect with regard to namespaces.
        at com.sun.org.apache.xerces.internal.dom.CoreDocumentImpl.checkDOMNSErr
(CoreDocumentImpl.java:2421)

the following log trace was also present in the log file

SEVERE: SAAJ0511: Unable to create envelope from given source

Apparently I run onto a known java bug present in jdk1.5.0_08 up to jdk1.5.0_11. Funny, I downgraded to jdk1.5.0_07.