If statements

So I’m trying to make an action that will make a little dot appear once the loading sequence gets past a certain point, the dot (set at alpha 0) is in a movie clip on the first frame of the document, and I don’t understand why it doesn’t work…

if ((_root.getBytesLoaded()/_root.getBytesTotal()) * 100) >= 8.3) {
    setProperty("LD1", _alpha, "100"); ;
}

it should be a simple if…then statement, but that doesn’t work…

Help would be wonderful!