Biztalk 2009 webservice error

Hi i created an orchestration and exposed it as a web service on my xp test machine but i am getting a wierd error when i try to consume the webservice. I’ve read some posts that say it has something to do with the iis configuration and i should create a virtual directory in iis and set the application permissions but that still does not work any ideas. Here is the error:

System.Web.Services.Protocols.SoapException: Internal SOAP Processing Failure

   at Microsoft.BizTalk.WebServices.ServerProxy.ServerProxy.Invoke(String functionName, Object[] parameters, ParamInfo[] inParamInfos, ParamInfo[] outParamInfos, Int32 bodyPartIndex, String bodyType, ArrayList inHeaders, ArrayList inoutHeaders, ArrayList& inoutHeaderResponses, ArrayList& outHeaderResponses, Type[] outHeaderTypes, String[] outHeaderNamespaces, SoapUnknownHeader[] unknownHeaders, SoapUnknownHeader[]& unknownHeaderResponses, Boolean oneway, Boolean spsSsoEnabled, Object cookie)

   at Microsoft.BizTalk.WebServices.ServerProxy.ServerProxy.Invoke(String functionName, Object[] parameters, ParamInfo[] inParamInfos, ParamInfo[] outParamInfos, Int32 bodyPartIndex, String bodyType, ArrayList inHeaders, ArrayList inoutHeaders, ArrayList& inoutHeaderResponses, ArrayList& outHeaderResponses, Type[] outHeaderTypes, String[] outHeaderNamespaces, SoapUnknownHeader[] unknownHeaders, SoapUnknownHeader[]& unknownHeaderResponses, Boolean oneway, Boolean spsSsoEnabled)

   at ExposeWebService.Microsoft_Samples_BizTalk_ExposeWebService_ProcessClientRequest_SOAPPort.Operation_1(ClientRequest MessagePart_1)

can anyone help me on this im stuck.