OpenSAML user discussion

The following Exception occurred when I tried to sign a SAMLRequest to be 
included in SAMLSOAPBinding:

java.lang.ClassCastException
        at org.apache.xerces.dom.DeferredTextImpl.synchronizeData(Unknown 
Source)
        at org.apache.xerces.dom.NodeImpl.setOwnerDocument(Unknown Source)
        at org.apache.xerces.dom.ParentNode.setOwnerDocument(Unknown Source)
        at org.apache.xerces.dom.ElementImpl.setOwnerDocument(Unknown Source)
        at org.apache.xerces.dom.ParentNode.setOwnerDocument(Unknown Source)
        at org.apache.xerces.dom.ElementImpl.setOwnerDocument(Unknown Source)
        at org.apache.xerces.dom.CoreDocumentImpl.adoptNode(Unknown Source)
        at org.opensaml.SAMLSubject.toDOM(Unknown Source)
        at org.opensaml.SAMLObject.toDOM(Unknown Source)
        at org.opensaml.SAMLAuthenticationQuery.toDOM(Unknown Source)
        at org.opensaml.SAMLRequest.toDOM(Unknown Source)
        at org.opensaml.SAMLObject.toDOM(Unknown Source)
        at org.opensaml.SAMLObject.toDOM(Unknown Source)
        at org.opensaml.SAMLSignedObject.toDOM(Unknown Source)
        ...

At first, I thought it was something to do with the signature, so I commented 
out the signature part of my code. However, the same Exception occurred.

There are no line sources so I have no way of finding out where the Exception 
occurs.

Anyone has had a similar problem? Thank you!

Regards
Bernard