Solving Index Out of Bounds on Input.GetTouch(0) in an if statement

Hi everyone, hope you can help me with this.

I've been trying to script a simple game where a player throws 3D Junk into a rubbish bin using swipe gestures on a touch device.

I'm getting an error "Index out of Bounds on line 74 of the following script.

"ArgumentException: Index out of bounds. ShootFINAL.FixedUpdate () (at Assets/Scripts/ShootFINAL.cs:74) " can someone explain what the problem is? Its probably something simple!

 using UnityEngine;
 using System.Collections;
 
 /* Contained Logic:
  * Touch Detection 
  * Shot Detection/restrictions
  * Swipe debugging(disabled)
  * 
  * Author: Conall Ó
 */
 
 
 public class ShootFINAL : MonoBehaviour {
 
 private Vector3 touchStart; 
 private Vector3 touchEnd;
 private GameObject lineRenderer;
     
 public GameObject cokecan;
 private GameObject cokecanClone;
 public Vector3 ballPos;
 private bool throwable = true;
 public GameObject availableShotsGO;
 private int availableShots = 10;
 
 public GameObject gameOver;
 public float restartDelay = 4f;
 float restartTimer;
 private bool restarting = false;
     // Use this for initialization
     void Start()
     {
         /* Increase  vertical Gravity */
         Physics.gravity = new Vector3(0, -25, 0);
          
     }
 
     void OnGUI () // ignore this debugging stuff.
     {
         
         foreach (Touch touch in Input.touches) {
             string message = "";
             message += "Finger ID: " + touch.fingerId + "\n";
             message += "Phase: " + touch.phase.ToString () + "\n";
             message += "TapCount: " + touch.tapCount + "\n";
             message += "Pos X: " + touch.position.x + "\n";
             message += "Pos Y: " + touch.position.y + "\n";
             message += "Input.TouchCount: " +Input.touchCount + "\n";
             int num = touch.fingerId;
             GUI.Label (new Rect (0 + 130 * num, 0, 120, 100), message);
             
         }
 
     }
     void FixedUpdate () {
 
 
     if (Input.touchCount > 0) {
 // if there is a touch,    then execute.    
             Debug.Log ("Touchcount >0 detected");
         
 
             if (throwable == true) {
 
                 throwable = false; //set the ball to "thrown" so we can't throw two at the same time
                 availableShots--; // decrement number of shots left
                 availableShotsGO.GetComponent<GUIText> ().text = availableShots.ToString (); // Add the shots remaning as text to our GUI.
                 Debug.Log ("Shot Detected");
     
             }
         }
 
 
             if (Input.GetTouch(0).phase == TouchPhase.Began) {
                 touchStart = Input.GetTouch(0).position;
             }
             
             if (Input.GetTouch(0).phase == TouchPhase.Ended || Input.GetTouch(0).phase == TouchPhase.Canceled) {
                 touchEnd = Input.GetTouch(0).position;
                 DoInput ();
             }
 
 
         
         if (Input.GetButtonDown ("Fire1")) {
             touchStart = Input.mousePosition;
         }
         
         if (Input.GetButtonUp ("Fire1")) {
             touchEnd = Input.mousePosition;
             DoInput ();
         }
 
 
 }
     void Update()
     {
 
         if (Input.touchCount > 0)
             Debug.Log ("Touches detected: " + Input.touchCount);
 
         /* Check if out of shots / Game over */
         
         if (availableShots <= 0) {
             Application.LoadLevel("GameOver");
 
 
             if (restartTimer >= restartDelay) {
                 Application.LoadLevel (Application.loadedLevel);
                 restarting = false;
             }
             
         }
 
     }
     
     void DoInput()
     {
         Vector3 p1 = new Vector3();
         Vector3 p2 = new Vector3();
         touchStart.z = Camera.main.nearClipPlane+.1f; //push it a little past the clip plane for camera, just to make sure its visible on screen
         touchEnd.z = Camera.main.nearClipPlane+.1f;
         p1 = Camera.main.ScreenToWorldPoint(touchStart);
         p2 = Camera.main.ScreenToWorldPoint(touchEnd);
         
         // CreateLine(p1,p2); - Swipe Debugging line creation on input - SWIPE DEBUGGING
         CreateLine (p1, p2);
 
         Vector3 v = p2-p1;
 
         if (throwable == true) {
             cokecanClone = Instantiate (cokecan, ballPos, transform.rotation) as GameObject;
             cokecanClone.GetComponent<Rigidbody> ().AddForce (v.x * 100, v.y * 120, v.y * 300, ForceMode.Impulse);
             throwable = false;
 
         }
     }
     
 
     //     SWIPE DEBUGGING
     //creates an ugly purple line from pos1 to pos2 in worldspace
     void CreateLine(Vector3 p1, Vector3 p2)
     {
         Destroy(lineRenderer);
         lineRenderer = new GameObject();
         lineRenderer.name = "LineRenderer";
         LineRenderer lr = (LineRenderer)lineRenderer.AddComponent(typeof(LineRenderer));
         lr.SetVertexCount(2);
         lr.SetWidth(0.001f, 0.001f);
         lr.SetPosition(0, p1);
         lr.SetPosition(1, p2);
     }
 
 
 
 
 
     void restart()
     {
         Application.LoadLevel(Application.loadedLevel);
     }
 
 }