Interval problem

Hi,

I have an interval problem. Here is the code.

//function for fading in objects
function fadeIn(theMc:MovieClip, fadeParam:Number) {
    if (theMc._alpha < 100) {
        theMc._alpha += fadeParam;
		trace(theMc._alpha);
    }
    else {
		theMc._alpha = 100;
		trace(theMc._alpha);
		clearInterval(theMc.fadeInID);
    }
}

introFoto.fadeInID = setInterval(fadeIn, 40, introFoto, 5);

I made a small function for fading in objects. Once the object its alpha is larger then 100, it should stop that interval, but it doesn’t. Can sombody tell me why and what I have to do.

thanx in advance