Getting "An attempt is made to create or change an object ..." in one env.

Question

I have a colleague who wrote some JAX-WS client code using what WebLogic 10.3.3 provides out of the box. His code is creating a "wsse:Security" element by using SOAPFactory and SOAPElement and related classes. This has worked fine on a couple of dev boxes. They've now promoted the deployment to the next environment, and now the attempt to add the constructed "Security" element fails with:
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.
They have verified the problem environment is running the same version of the JDK and WebLogic, but they haven't yet confirmed they have the same WebLogic patches.
I repeat, this is working fine on his development environment and on at least two development servers, and is having this problem on the next environment down the line towards production.
I looked for some other experiences with this error, and the only substantive code suggestion I found from that was to add all the used namespaces to the envelope. He did that, but it didn't make a difference.
The relevant block of code is the following (it fails on the last line):
                    SOAPEnvelope envelope = soapMsgContext.getMessage().getSOAPPart().getEnvelope();
                    SOAPFactory soapFactory = SOAPFactory.newInstance();
                    // WSSecurity <Security> header
                    SOAPElement wsSecHeaderElm = soapFactory.createElement(
                              "Security",
                              AUTH_PREFIX,
                              AUTH_NS);
                    QName wsSecHdrMustUnderstandAttr = new QName("S:mustUnderstand");
                    wsSecHeaderElm.addAttribute(wsSecHdrMustUnderstandAttr, "1");
                    SOAPElement userNameTokenElm = soapFactory.createElement("UsernameToken",
                              AUTH_PREFIX,
                              AUTH_NS);
                    Name userNameTokenIdName = soapFactory.createName(
                              "id",
                              "wsu",
                              "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd");
                    userNameTokenElm.addAttribute(userNameTokenIdName, "Id-8zvykuwmK8yg6dxn3632nQJB");
                    SOAPElement userNameElm = soapFactory.createElement("Username",
                              AUTH_PREFIX,
                              AUTH_NS);
                    userNameElm.addTextNode(userName);
                    SOAPElement passwdElm = soapFactory.createElement("Password",
                              AUTH_PREFIX,
                              AUTH_NS);
                    Name passwdTypeAttr = soapFactory.createName("Type");
                    passwdElm.addAttribute(passwdTypeAttr, "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText");
                    passwdElm.addTextNode(password);
                    userNameTokenElm.addChildElement(userNameElm);
                    userNameTokenElm.addChildElement(passwdElm);
                    // add usernametoken to Security header
                    wsSecHeaderElm.addChildElement(userNameTokenElm);
                    // create SOAPHeader instance for SOAP envelope
                    SOAPHeader sh = envelope.getHeader();
                    // add SOAP element for header to SOAP header object
                    sh.addChildElement(wsSecHeaderElm);
-------------------------

Answer 1

if it matters, after extensive gnarly debugging, we found the problem was this expression:
new QName("S:mustUnderstand")
When we changed this to properly specify the prefix and namespace, the environment it was failing on worked.
What was odd about this is that other server environments seemingly using the same jars (we turned on verbose:class to verify this) had no problem with this code.
What was really annoying about this problem is that the error message could have been much more informative. I'm sure the code reporting the error must have known it was this attribute that was having the problem, but it only gave us a very vague error message about the entire element we were creating, which had several sub-elements.