Animation problem in script

Sry bout all these newbie questions guys lol. Anyways, I have these animations for walking and sprinting. I have it so when u press the w key it loops and when u let the button go. Ok so that works perfectly, but when I tried to do that with sprinting it doesn't run either animation. What's up with that? Here's my code. It's a modify of the Character motor script on the FPC:

 var walkSpeed: float = 7; // regular speed
 
 var crchSpeed: float = 3; // crouching speed
 
 var runSpeed: float = 20; // run speed
 
 
 
 private var chMotor: CharacterMotor;
 
 private var tr: Transform;
 
 private var dist: float; // distance to ground
 
 
 
 function Start(){
 
     chMotor = GetComponent(CharacterMotor);
 
     tr = transform;
 
     var ch:CharacterController = GetComponent(CharacterController);
 
     dist = ch.height/2; // calculate distance to ground
 
 }
 
 
 
 function Update(){
 
 
 
     var vScale = 1.0;
 
     var speed = walkSpeed;
 
     
 
     if (Input.GetKey("left shift") || Input.GetKey("right shift")){
 
         if (Input.GetKey(KeyCode.W))
 
         {
 
         speed = runSpeed;
 
         GameObject.Find("FPS_m16").animation.Stop("Walking");
 
         GameObject.Find("FPS_m16").animation.CrossFade("Sprinting");
 
         }
 
     }
 
     if (Input.GetKey("left shift") || Input.GetKey("right shift"))
 
     {
 
         GameObject.Find("FPS_m16").animation.Stop("Sprinting");    
 
     }
 
     
 
     if (Input.GetKey("c")){ // press C to crouch
 
         vScale = 0.5;
 
         speed = crchSpeed; // slow down when crouching
 
     }
 
     if (Input.GetButtonDown("Walk")){
 
         GameObject.Find("FPS_m16").animation.CrossFade("Walking");
 
     }
 
     if (Input.GetButtonUp("Walk")){
 
         GameObject.Find("FPS_m16").animation.Stop("Walking");
 
     }
 
     chMotor.movement.maxForwardSpeed = speed; // set max speed
 
     var ultScale = tr.localScale.y; // crouch/stand up smoothly 
 
     tr.localScale.y = Mathf.Lerp(tr.localScale.y, vScale, 5*Time.deltaTime);
 
     tr.position.y += dist * (tr.localScale.y-ultScale); // fix vertical position
 }

Thanks!