i updated my unity 5. and now getting errors

this script was working fine in older unity version now it has errors and no scenes will play

its 2d so why is error asking about rigidbody 2d its definitely a 2d game

error is Assets/Standard Assets/Scripts/General Scripts/DragRigidbody.js(30,18): BCE0019: 'rigidbody2D' is not a member of 'UnityEngine.RaycastHit'. Did you mean 'rigidbody'?

 var spring = 50.0;
 var damper = 5.0;
 var drag = 10.0;
 var angularDrag = 5.0;
 var distance = 0.2;
 var attachToCenterOfMass = false;
 
 var  Idle: AnimationClip;
 private var springJoint : SpringJoint;
 
 function Update ()
 {
 
 if (Mathf.Abs(Input.GetAxis("Vertical")) <= 0.1){
         GetComponent.<Animation>().CrossFade("Idle");
     }
 
     // Make sure the user pressed the mouse down
     if (!Input.GetMouseButtonDown (0))
         return;
 
     var mainCamera = FindCamera();
         
     // We need to actually hit an object
     var hit : RaycastHit;
     if (!Physics.Raycast(mainCamera.ScreenPointToRay(Input.mousePosition),  hit, 100))
         return;
     // We need to hit a rigidbody that is not kinematic
     if (!hit.rigidbody2D || hit.rigidbody2D.isKinematic)
         return;
     
     if (!springJoint)
     {
         var go = new GameObject("Rigidbody2D dragger");
         var body : Rigidbody2D = go.AddComponent.<Rigidbody2D>() as Rigidbody2D;
         springJoint = go.AddComponent.<SpringJoint>();
         body.isKinematic = true;
     }
     
     springJoint.transform.position = hit.point;
     if (attachToCenterOfMass)
     {
         var anchor = transform.TransformDirection(hit.rigidbody2D.centerOfMass) + hit.rigidbody2D.transform.position;
         anchor = springJoint.transform.InverseTransformPoint(anchor);
         springJoint.anchor = anchor;
     }
     else
     {
         springJoint.anchor = Vector3.zero;
     }
     
     springJoint.spring = spring;
     springJoint.damper = damper;
     springJoint.maxDistance = distance;
     springJoint.connectedBody = hit.rigidbody2D;
     
     StartCoroutine ("DragObject", hit.distance);
 }
 
 function DragObject (distance : float)
 {
     var oldDrag = springJoint.connectedBody.drag;
     var oldAngularDrag = springJoint.connectedBody.angularDrag;
     springJoint.connectedBody.drag = drag;
     springJoint.connectedBody.angularDrag = angularDrag;
     var mainCamera = FindCamera();
     while (Input.GetMouseButton (0))
     {
         var ray = mainCamera.ScreenPointToRay (Input.mousePosition);
         springJoint.transform.position = ray.GetPoint(distance);
         yield;
     }
     if (springJoint.connectedBody)
     {
         springJoint.connectedBody.drag = oldDrag;
         springJoint.connectedBody.angularDrag = oldAngularDrag;
         springJoint.connectedBody = null;
     }
 }
 
 function FindCamera ()
 {
     if (GetComponent.<Camera>())
         return GetComponent.<Camera>();
     else
         return Camera.main;
 }