Error #2006: The supplied index is out of bounds

Question

hello,
i'm trying to addChild with an interval, using this piece of code, but I allways get an error saiyng the suplied index is out of bounds.
why?
what should I do to have mc1 added then wait lets say a second and add m2 2 and so on?
Thanks
var tempo_espera:Timer = new Timer(1000, 1);
            tempo_espera.addEventListener("timer", inserir);
            tempo_espera.start();
            function inserir(evt:TimerEvent):void {
                for (var nv1:int = 0; nv1<promocoes.length; nv1++) {
                    holder.addChildAt(mc, nv1);
                    var animacao:TransitionManager = new TransitionManager(mc);
                    animacao.startTransition({type:Zoom, direction:Transition.IN, easing :Elastic.easeOut, duration:3});
RangeError: Error #2006: The supplied index is out of bounds.
at flash.display::DisplayObjectContainer/addChildAt()
at MethodInfo-346()
at flash.utils::Timer/_timerDispatch()
at flash.utils::Timer/tick()

Answer 1

using your new code, I got this error
TypeError: Error #2007: Parameter child must be non-null.
at flash.display::DisplayObjectContainer/addChild()
at MethodInfo-343()
at flash.utils::Timer/_timerDispatch()
at flash.utils::Timer/tick()
I had to add mcArray = new Array(); to avoid another error
// this is array of movie clips
        var mcArray:Array;
        // it is better to declare variable once and then reinstantiate it
        var mc:MovieClip;
        // do your regular routine
        for (var nv:uint = 0; nv<promocoes.length; nv++) {
            var prm;
            prm = promocoes[nv].split("|sep|");
            mc = new MovieClip();
            mc.name = "mc_"+nv;
            // place this new mc into array
            mcArray = new Array();
            mcArray.push(mc);
        // start timer - note that timer will fire as many times as there are movie clips
        var tempo_espera:Timer = new Timer(1000, mcArray.length);
        tempo_espera.addEventListener("timer", placeClip);
        tempo_espera.start();
        // the clip you will apply transition to
        var currentClip:MovieClip;
        // function that places clips
        function placeClip(e:Event):void {
            // get next clip by calling movie that corresponds with the timer counter
            currentClip = MovieClip(mcArray[tempo_espera.currentCount]);
            // just place next clip
            holder.addChild(currentClip);
            var animacao:TransitionManager = new TransitionManager(currentClip);
            animacao.startTransition({type:Zoom, direction:Transition.IN, easing :Elastic.easeOut, duration:3});