Vuforia Raycasting Problem

Im using code below to get object touched by finger and place it in popup cam. It is working perfect on normal unity camera i tested it, but when i place this code in vuforia ARCamera its is not working , for some reason…Any idea?

FIXED

Hello all,
I have attached the below code to the AR Camera as to detect the different augmentations and drag them using touch input.
This piece of code works fine with default camera but with the AR Camera and touch input, this doesn’t seem to work.
Also I have a specific doubt. The AR Camera prefab that comes with Vuforia has a child camera tagged by default as Main Camera.
So being a newbie to Unity and Vuforia, I am not able to figure out to which of these should i attach my codes. I have tried changing the layer of AR Camera, its child and the objects on the scene to a separate layer(eg layer 10). but it doesnt seem to work too
Hoping to receive some inputs.

using UnityEngine;
using Vuforia;
using System.Collections;
using System.IO;
using UnityEngine.UI;

public class trial : MonoBehaviour {

private GameObject focusObj = null;
private float focusx;
private float focusy;
private float focusz;

void Update()
{

if(Input.touchCount>0 && Input.GetTouch(0).phase==TouchPhase.Began)
{
focusObj = null;
Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
RaycastHit hit;

if(Physics.Raycast(ray, out hit, Mathf.Infinity))

{
focusObj=hit.transform.gameObject;
}
}

if(focusObj && Input.touchCount >0 && Input.GetTouch(0).phase == TouchPhase.Moved)
{
focusx= Input.GetTouch(0).deltaPosition.x/500;
focusz= 0;
focusy= Input.GetTouch(0).deltaPosition.y/500;

Vector3 pos = new Vector3(focusx, focusz, focusy);
focusObj.transform.position += pos;

}
if(focusObj && Input.touchCount >0 && Input.GetTouch(0).phase == TouchPhase.Ended)
{
focusObj=null;
}

}
}