problem with loading external gif image - Macromedia Flash

Hi
I want to load gif image form external url but it didn't work but the same
action work with .jpg file. why ?

Note:
I'm using flash cs3 & AS 2.0

code I m using

var mcHolder:MovieClip = this.createEmptyMovieClip("mcHolder",
this.getNextHighestDepth());
var mclLoader:MovieClipLoader = new MovieClipLoader();
var oListener:Object = new Object();
mclLoader.addListener(oListener);

oListener.onLoadInit = function(mcContent:MovieClip) {
mcContent._xscale = 35;
mcContent._yscale = 35;
}


mclLoader.loadClip("http://192.168.1.185/bostonusa/images/stories/backbay.gif
", _root.popup1.image_mc);


but instead of given url if I use
http://192.168.1.185/bostonusa/image...FreeTicket.jpg
it wil work.
Please reply me ASAP.

Thanks