function getError(errorObject)
{
  var Error = new String;
  Error  ="Error. " + errorObject.parseError.url + "<br />"
          + "Line: " + errorObject.parseError.line + "<br />"
          + "Description: " + errorObject.parseError.reason;
  return Error;
}

Returns the file (XML or XSLT Document), the error line and the reason

Example, running the Dillard document and a Modified Version with an error