Problems using CXF proxy web service in Mule 2.0.2

The error message is :

org.apache.cxf.interceptor.Fault: Marshalling Error: class org.apache.cxf.staxutils.DepthXMLStreamReader nor any of its super class is known to this context.

Everything seems to work fine until an exception is thrown when returning the response from the proxied web service.

I am including a log file, my service class that is being proxied to, and a mule-config.xml that I am running.

Any help would be appreciated.
SAMLTestServicePortTypeImpl.javamule-config.xmlerror.log