ActionScript 2.0 :: Tween Setup - Symbol Jump To Center Of Stage?

I have a tween set up in actionscript... something like this
Code:
function tween(){
var tweenPart1:Tween = new Tween(_root.tweenMe), "_x", Strong.easeOut, 100, 50, 3, true);
}
That isn't the problem... it actually works very well.

But I also have another peice of script.
Code:
_root.tweenMe.onEnterFrame = function (){
this.onRollOver = function(){
this._x = 50
}}

This just counter-acts the tween to make the symbol jump to the centre of the stage and then stop. but that is the problem... the symbol wont stop. it jumps to 50 for about 0.1 sec then continues with the tween.
PS tweenPart1.stop(); doesn't work for some reason