TypeError: Error #1034: Type Coercion failed

hi , i use an ready Accordion Panel in Flash ( here )

now when i add any button on this frame i get this error when i click Accordion tabs :

TypeError: Error #1034: Type Coercion failed: cannot convert flash.display::SimpleButton@48596ab9 to flash.display.MovieClip.

and when i add movieclip to the stage i get this error right after click on any Accordion panels :

TypeError: Error #1010: A term is undefined and has no properties.     at mobver2_fla::MainTimeline/onClick()

here is the main script for Accordion panel :

import gs.*;
import gs.easing.*;

panel1.props = {ly:53, ry:650, ind:1};
panel2.props = {ly:115, ry:700, ind:2};
panel3.props = {ly:169, ry:750, ind:3};

panel1.addEventListener(MouseEvent.CLICK, onClick);
panel2.addEventListener(MouseEvent.CLICK, onClick);
panel3.addEventListener(MouseEvent.CLICK, onClick);

function onClick(e:MouseEvent):void
{
    var clicked:MovieClip = MovieClip(e.target);    for(var i:int=0; i<numChildren; i++)    {        var mc:MovieClip = MovieClip(getChildAt(i));        if(mc.props.ind <= clicked.props.ind)            TweenLite.to(mc, 1, {y:mc.props.ly, ease:Bounce.easeOut});        else            TweenLite.to(mc, 1, {y:mc.props.ry, ease:Bounce.easeOut});    }
}

it seems this script effect on all movieclip or buttons in Frame , but i cant figure it out how i must separate other buttons and movieclips from this . i really need to add some button and movie clip to these panels and frame