communicating to btns in a loaded swf

I am using the following code to try to reference these buttons "withing" my loaded content – itis giving me the following error:

TypeError: Error #1010: A term is undefined and has no properties.
    at sliSiteFinal_2_fla::MainTimeline/prevOut()

code:

pPrevH.addEventListener (MouseEvent.MOUSE_OUT, prevOut);

function prevOut (e:MouseEvent):void{
    var mc:MovieClip = MovieClip(imageLoader.content);
    mc.btn_prev.gotoAndPlay ("pLout");

Is my dot syntax here off? As it seems I am defining prevOver and it is telling me I am not.

Thanks!