problema preload e NaN

[serialkiller]

onClipEvent (load) {
_root.stop();
}
onClipEvent (enterFrame) {
car = _root.getBytesLoaded();
tot = _root.getBytesTotal();
perc = int(car/tot*100);
_root.percentuale = perc+"%";
if (car == tot) {
_root.nextFrame();
}
}


SK