Script does not work on version 4.6.0.

Hi! In unity 3d 3.5.7 I used this script. Now since I use the version 4.6.0 this script does not work as it should.

 var other : Motion; // assign the game object having the animation BOX OR BALL
 
 function OnTriggerEnter (collision : Collider) 
                 { 
    if ((collision.gameObject.tag == "alien attack") )//here put the the tag for the game object box where you want to hit the ball
 
                     {
                 other.Play("attack"); 
                     }
                 
                                   
                  }

To insert the animation of the character I changed the variable to Animation in Motion.

When I enter the cube triggers, the character should attacarmi but this does not happen. Against which the probblema in this script?