Animate On Mouseover On Lower Layer?

So, I had a problem animating a movie clip on mouseover which was solved here: http://forums.adobe.com/thread/496745?tstart=0 Now the problem I'm having is that I want to movie some of those clips to a lower layer so that they animate behind an object on the top layer.If I put the same code on that bottom layer as in the top layer,
 
leaf.addEventListener(MouseEvent.ROLL_OVER,doStartAnim);  

it tells me that I have a duplicate function definition.If I cut out the second half of the code,

function doStartAnim(e:MouseEvent):void {
e.currentTarget.play();
e.currentTarget.removeEventListener(MouseEvent.ROLL_OVER,doStartAnim) ;
}

and just put that other part it doesn't give me the error, but mousing over the leaf does nothing. Any thoughts?
 
P.S. - If I leave the entire code for the movie on the top layer (with the movie on a seperate background layer) I get the following error:
 
Description: 1120: Access of undefined property leaf5. Source: leaf5.addEventListener(MouseEvent.ROLL_OVER,doStartAnim);I hope that all makes sense!