function gupOver(evenet:MouseEvent):void{	
for(var i:Number = 0; i < 10; i++){
		if (this.thumContainer_mc.y >= 166){
			thumContainer_mc.y -= i;
		}else{
			break;
			}
      }
	}
			
function gdownOver(event:MouseEvent): void{	
for(var j:Number = 0; j < 10; j++){
	    if(this.thumbContainer_mc.y >= 290.9){
			stop();
		}else{
			thumContainer_mc.y += j;
			}
	}

	}

error
TypeError: Error #1010: A term is undefined and has no properties.
	at main_fla::MainTimeline/gdownOver()