Cant loadMovie unless im on _root

Alright im trying to attach a thumbnail to a nested movie clip through XML. The code I have right now is


var livexml = new XML();
livexml.ignoreWhite = true;
livexml.onLoad = function(success) {
    if (success) {
        livelength = livexml.firstChild.firstChild.childNodes.length;
        live = livexml.firstChild.firstChild.childNodes;
        for (i=0; i<livelength; i++) {
            _root.content.window.gallery.attachMovie("thumb", "thumb"+i, _root.getNextHighestDepth());
            _root.content.window.gallery["thumb"+i]._x = i*100;
            _root.content.window.gallery["thumb"+i]._y = 400;
            _root.content.window.gallery["thumb"+i].thumbnail.loadMovie("photos/livetn/"+livexml.firstChild.firstChild.childNodes*.attributes.src);
        }
    } else {
        trace("Error loading XML file");
    }
};
livexml.load("live.xml");

That isnt working for some reason…If I replace _root.content.window.gallery with just _root it works fine. The thing is I dont want it on the _root I want it where my code is pointing to now. This xml exists on my gallery mc by the way. Any pointers please?