Touch Manager not accepting GUITexture

This following code is my Unity(C#) Touch Manager Script that simply tells the results of hit test to its children:

public static bool guiTouch = false;

     public void TouchInput (GUITexture texture)
     {
         if (texture.HitTest(Input.GetTouch(0).position))
         {
             switch(Input.GetTouch(0).phase)
             {
                 case TouchPhase.Began:
                 SendMessage("OnFirstTouchBegan");
                 guiTouch = true;
                 break;
 
             case TouchPhase.Stationary:
                 SendMessage("OnFirstTouchStayed");
                 guiTouch = true;
                 break;
                 case TouchPhase.Moved:
                 SendMessage("OnFirstTouchMoved");
                 guiTouch = true;
                 break;
                 case TouchPhase.Ended:
                 SendMessage("OnFirstTouchEnded");
                 guiTouch = false;
             break;
 
         }

I've accessed it with the following script:

 using UnityEngine;
 using System.Collections;
 
 public class SquareTouchedDetector : TouchManager {
     public GUITexture texture;
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
 
         TouchInput (texture);
     }
     void OnFirstTouchBegan ()
     {
         SendMessage ("Tappin' works!!");
     }
 }
 

For some reason after being given the GUITexture it so much desires it gives me this error:
ArgumentException: Index out of bounds. TouchManager.TouchInput(UnityEngine.GUITexture texture)(at Assets/Scripts/TouchManager.cs:13)

Your help is very much appreciated as I am somewhat knew to Unity C# and am trying to get my first game in the store. Thanks in advance :)