Why Isn't My Raycast Working?

I have a script that casts a ray down the center of the screen and it finds the distance of objects and other stuff, it worked fine yesterday, but today it isn't finding distance and I assume it's because it's not even being cast in the first place. If anyone knows what is wrong I would really appreciate help.

 #pragma strict
 
 var Distance : int;
 var Holding = false;
 
 private var lineTransform : Vector3;
 private var startTransform : Vector3;
 
 function Update ()
 {
     if (Input.GetButtonDown("Fire1"))
     {
             Path();
     }
 }
 
 function Path()
 {
 
 var hit : RaycastHit;
 var ray : Ray = Camera.main.ScreenPointToRay(Vector3(Screen.width*0.5, Screen.height*0.5, 0));
 
 {
     if(Holding == false)
     {
         if (Physics.Raycast (ray, hit, 100))
         {
             Distance = hit.distance;
             
             if(hit.transform.tag == "PickUp")
             {
                 hit.transform.parent = transform;
                 hit.rigidbody.useGravity = false;
                 Holding = true;
             
                 lineTransform = hit.point;
         }
     }
     if(Holding == true)
     {
         if (Physics.Raycast (ray, hit, 100))
         {
             Distance = hit.distance;
             
             if(hit.transform.tag == "PickUp")
             {
                 hit.transform.parent = null;
                 hit.rigidbody.useGravity = true;
                 Holding = false;
             
                 lineTransform = hit.point;
             }
         }
     }
 }
 }
 }