Why doesn't my GUI.Label show up?

I have a script I have been working on, but the GUI.Label won’t show up! Check my code please!

var score = 0;

function OnGUI () {
    GUI.Label(new Rect(10, 10, 500, 200), "Score: " + score.ToString());
}

Put a close bracket " ) ", at the end of line 4, if that doesn’t work then check the console and post the whole script