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;
}

The error indicates that you are attempting to pull a variable called rigidbody2D from a RaycastHit object, RaycastHit does not contain a variable by that name, it does contain a variable called “rigidBody” but this is of Type RigidBody if you are making a 2D game you may need to be using the 2D physics raycasting instead.

This will give you back the hit object as a RaycastHit2D which has a variable of rigidBody but this time of type “RigidBody2D”.