[Actionscript 2] trying to find redirect url

I am trying to load a url and find the redirect url. It works fine in IE6 and Mozilla, however IE7 does not work. I only get back the original url. Below is my code

createEmptyMovieClip (“mc”, getNextHighestDepth ());
var _mcl:MovieClipLoader = new MovieClipLoader ();
_mclListener = new Object ();
_mclListener.onLoadStart = function (target:MovieClip)
{

var _lv:LoadVars = new LoadVars ();
_lv.decode (target._url.split ("?")[1]);

};

_mcl.addListener (_mclListener);

_mcl.loadClip (_level0.tempURL, mc);

Does anyone know why IE7 would have this issue?