SOAPClient invocation from ESB is failing with com.ctc.wstx.exc.WstxEOFException in SOA-P 5

Issue

• The following error is received when ESB action pipeline invokes SOAPClient to call a target WebService.

2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1) org.jboss.soa.esb.actions.ActionProcessingException: soapUI Client Service invocation failed.
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.actions.soap.SOAPClient.process(SOAPClient.java:447)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.processPipeline(ActionProcessingPipeline.java:665)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline.access$000(ActionProcessingPipeline.java:85)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline$1.run(ActionProcessingPipeline.java:1041)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.listeners.message.ActionProcessingPipeline$1.run(ActionProcessingPipeline.java:1038)
...
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1) Caused by: java.io.IOException: Failed to deserialize the SOAP message template
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.services.soapui.SoapUIClientService.getDocument(SoapUIClientService.java:714)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.services.soapui.SoapUIClientService.mergeSOAPMessage(SoapUIClientService.java:603)
2013-11-08 14:56:49,880 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.services.soapui.SoapUIClientService.mergeResponseTemplate(SoapUIClientService.java:491)
...
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1) Caused by: com.ctc.wstx.exc.WstxEOFException: Unexpected EOF in prolog
 at [row,col {unknown-source}]: [1,0]
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.sr.StreamScanner.throwUnexpectedEOF(StreamScanner.java:686)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.sr.BasicStreamReader.handleEOF(BasicStreamReader.java:2134)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.sr.BasicStreamReader.nextFromProlog(BasicStreamReader.java:2040)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1069)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.evt.WstxEventReader.nextEvent(WstxEventReader.java:196)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at com.ctc.wstx.evt.WstxEventWriter.add(WstxEventWriter.java:230)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.internal.soa.esb.util.XMLHelper.copyXMLEventStream(XMLHelper.java:344)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.internal.soa.esb.util.XMLHelper.copyXMLEventStream(XMLHelper.java:316)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.internal.soa.esb.util.XMLHelper.createDocument(XMLHelper.java:646)
2013-11-08 14:56:49,882 ERROR [STDERR] (pool-31-thread-1)       at org.jboss.soa.esb.services.soapui.SoapUIClientService.getDocument(SoapUIClientService.java:712)

What is the root cause behind this ERROR?