mmm.. prova così


// variabile globale

var loop:Number = 0;
var MAX:Number = 5;

// istanzia i cerchi

for (i=0; i<5; i++) {
trace(["cerchio"+i]);
duplicateMovieClip("cerchio"+i);
}

function startNextTween(){
loop++;
var twtemp:Tween = new Tween("cerchio"+loop,"_x",Strong.easeOut,100,500,1 ,true);

if(loop <= MAX){
twtemp.onMotionFinished = function(){
startNextTween();
}

}