SoapClient XElement

I would askyou for your help!

     DateTime date = Convert.ToDateTime("1900-01-01");
     VisionSoapClient vsc = new VisionSoapClient();
     XElement xdata = vsc.GetCikkek(date);
     string path = "/ramiris/cikkek.xml";
     xdata.Save(Server.MapPath(path));

I getthe followingerror message isreturned:

The IXmlSerializable type 'System.Xml.Linq.XElement' cannot be deserialized in
partial trust because it does not have a public parameterless constructor.
Please help!