Can`t retrieve SharePoint GetListItems from the BizTalk 2006 orchestration

My orchestration consist a part of shapes to retrieve list from SharePoint portal by GetListItems web service method.

Construct shape have the following code to prepare request to the web service:

GetListItemsReqMsg.listName = "{…GUID…}";

GetListItemsReqMsg.listView = "{…GUID…}";

GetListItemsReqMsg.rowFilter = "";

GetListItemsReqMsg.query = new System.Xml.XmlDocument();

GetListItemsReqMsg.query.LoadXml ("<Query/>");

GetListItemsReqMsg.viewFields = new System.Xml.XmlDocument();

GetListItemsReqMsg.viewFields.LoadXml ("<ViewFields/>");

GetListItemsReqMsg.queryOptions = new System.Xml.XmlDocument();

GetListItemsReqMsg.queryOptions.LoadXml ("<QueryOptions/>");

When i started my orchestration SoapException occurred with the message "Exception of type Microsoft.SharePoint.SoapServer.SoapServerException was thrown.".

Where is an error at my Construct shape code????????