Error 1136

I get Error 1136 :incorrect number of arguments, expected 1, for this code, and can’t figure out why:

public class SpaceWolf extends MovieClip {
public function SpaceWolf() {
StarBg();
}
}

public function StarBg() {

var star:Star = new Star();
for (var i:Number = 0; i < 70; i++){
star.x = (Math.floor(Math.random()*650));
star.y = (Math.floor(Math.random()*600));

addChild(star);
}
}
}

I’m kind of new to programming so It might be something basic. I don’t have any parameters or arguments in the function so I’m confused why I get that error. I’d appreciate any help from anyone, thanks.