OnCollisionEnter Push Object Problem

Hello Unity3D.i have a problem with my OnCollisionEnter Script.The problem is that i can't seem to push my opponent when in contact of an animation.For example.I have a character that does a certain animation that is suppose to send the opponent flying backwards.But when i do the animation to the opponent it plays but the opponent doesn't go anywhere.How can i make it that when my character plays the animation the opponent moves?If anyone knows how i can do this?Can you please tell me how?Because i suck when it comes to pushing object/characters.....

Heres the script.

 var player : GameObject;
 var enemy  : Transform;
 var myTransform : Transform;
 var Slash       : GameObject;
 var spawn       : Transform;
 
 
 
  
 function Awake() {
         myTransform = transform;
 }
 function Start() {
  
         enemy = GameObject.FindWithTag("Dummy").transform;
 }
   
     
 
 function OnCollisionEnter(collision : Collision){
  
  if(collision.gameObject.tag == "Dummy"){
  
   if(player.animation.IsPlaying("Sweep_Kick"))
 collision.transform.gameObject.animation.Play ("Stand_Air_Hit_back");
 Instantiate(Slash,spawn.transform.position,spawn.transform.rotation);
 }
 if(player.animation.IsPlaying("Violets_Bicycle_Kick")){
 enemy.transform.gameObject.animation.Play("Violets_Bicycle_Kick_Hit_Part_One");{
     }
 }
 if(player.animation.IsPlaying("Violets_Bicycle_Kick_Part_2")){
 enemy.transform.gameObject.animation.Play("Violets_Bicycle_Kick_Hit_Part_Two");{
     }
 }
 if(player.animation.IsPlaying("Lance_Kick_2")){
 if (collision.rigidbody)
 enemy.transform.gameObject.animation.Play("Air_Hit_Going_Up");{
 collision.rigidbody.AddForce (Vector3.up * 50000, ForceMode.Impulse);
 
     }
 }
 if(player.animation.IsPlaying("Falcon_Punch")){
 enemy.transform.gameObject.animation.Play("Hit_Flying");
 
 
  
      
          
     }
  }