[away3d] How animate this Collada File

[Wenderson]

this code:...


                        //loader = new Object3DLoader();
                        //loader = Collada.parse("mario.dae");
                        modelo1 = Collada.parse("mario.dae", {scaling:0.1,
material:"TexturaObj"});
                        visao.scene.addChild(modelo1);

                        skinAnimation = modelo1.animationLibrary.getAnimation
("default").animation as SkinAnimation;
                }

                /*Iniciar as listas*/
                private function iniciarListas():void
                {
                        addEventListener(Event.ENTER_FRAME, EnterFrame);
                }

                /*Navegação e renderização loop*/
                private function EnterFrame(event:Event):void
                {
                        skinAnimation.update(getTimer()*2/1000);

                        visao.render();
                }
        }
}

this generate error:

TypeError: Error #1009: Cannot access a property or method of a null
object reference.

help me pleaseeeee!