WebService - Failed to copy message

Hi, I've got problem when I call WebService I get error:

    com.mendix.modules.microflowengine.MicroflowException: javax.xml.ws.WebServiceException: Failed to copy a message
        at Integration.CallForLabel (CallWebservice : 'Call web service')

    Advanced stacktrace:
        at com.mendix.modules.microflowengine.MicroflowUtil.processException(MicroflowUtil.java:158)

    Caused by: com.mendix.systemwideinterfaces.MendixRuntimeException: javax.xml.ws.WebServiceException: Failed to copy a message
        at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:43)

    Caused by: javax.xml.ws.WebServiceException: Failed to copy a message 
...
...
Caused by: javax.xml.stream.XMLStreamException: XMLStreamReader not positioned at a document or element
    at com.sun.xml.stream.buffer.stax.StreamReaderBufferCreator.store(StreamReaderBufferCreator.java:145)

Anyone knows what is the cause of this error? I set loglevel on webservice to trace and get generated xml. That XML pasted to SoapUI works correctly and I get response.