I am now contemplating my code.
You can try removing the documentElement piece from the code and try. Therefore the code would look like this: 
js code:
            Debug.Trace (  xmldom.selectSingleNode ( '//statuses/status/text' ).text );
instead of this:
js code:
            Debug.Trace (  xmldom.documentElement.selectSingleNode ( '//statuses/status/text' ).text );