Error while executing ECC_SALESORDERCRTRC web service

hello,

I am getting error while executing the we service ECC_SALESORDERCRTRC using webservice navigator

XML Serialization Error. Object content does not correspond to Schema restrictions of type [http://sap.com/xi/APPL/SE/Global][BusinessDocumentMessageID.Content].

can any one tell me why am i getting this error ?

thanks in advance