function error(sMessage, oElement) {
				sMessage += serializeSingleElement(oElement);
				Log.error(sMessage, sCaller, sXMLPreprocessor);
				throw new Error(sCaller + ": " + sMessage);
			}
Throws an error with the given message, prefixing it with the caller identification
(separated by a colon) and appending the serialization of the given XML DOM element.
Additionally logs the message and serialization as error with caller identification
as details.

@param {string} sMessage
  an error message which must end with a space (and take into account that the
  serialized XML is appended)
@param {Element} oElement
  the XML DOM element