Fai così:

codice:
onClipEvent (load) {
    this._visible = 0;
    _root.stop();
}
onClipEvent (enterFrame) {
    if (_root.getBytesLoaded() == _root.getBytesTotal()) {
        nexScene();
    }
    this._visible = 1;
    perc = barra._xscale=Math.round((_root.getBytesLoaded()/_root.getBytesTotal())*100);
    percentuale = perc+"%";
}
NAP