rollOver class problem

programming flash
1

Hello,
I am trying to set up a .as package to handle all my rollover functions for my _mc’s that are acting as buttons in my fla file.
Here is the code I have .

package
{
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.MouseEvent;
import fl.controls.Button;

public class btnEffect extends MovieClip

{
	public function btnEffect()
	{
			this.buttonMode = true;
			this.addEventListener(MouseEvent.MOUSE_OVER, rollOn);
			this.addEventListener(MouseEvent.MOUSE_OUT, rollOff);
	}
	
	public function rollOn(event:MouseEvent):void
	{
		if (this.currentFrame >= this.totalFrames) 
		{
           delete this.onEnterFrame;
   		} 
	   else 
	   {
          this.nextFrame(); 
       }
	
		//this.gotoAndStop(2);
	}
	
	public function rollOff(event:MouseEvent):void
	{
		this.gotoAndStop(1);
	}
}

}

I just started using AS3 and I am not all that familiar with the new updates to the code.
I keep getting this error message.
1119: Access of possibly undefined property onEnterFrame through a reference with static type btnEffect.