Cursor lock not working

I set tab as my fire3 on input and when I go to the game it doesn't lock the cursor or show any difference when pressing escape.

I also am using a hide cursor script on my char controller could this be effecting it?

The script is using UnityEngine; using System.Collections;

 public class CursorLock : MonoBehaviour {
 void DidLockCursor() {
 Debug.Log("Locking cursor");
 if (Input.GetKeyDown("Fire3" ))
 guiTexture.enabled = false;
 }
 void DidUnlockCursor() {
 Debug.Log("Unlocking cursor");
 guiTexture.enabled = true;
 }
 void OnMouseDown() {
 Screen.lockCursor = true;
 }
 private bool wasLocked = false;
 void Update() {
 if (Input.GetKeyDown("escape"))
 Screen.lockCursor = false;
 
 if (!Screen.lockCursor && wasLocked) {
 wasLocked = false;
 DidUnlockCursor();
 } else
 if (Screen.lockCursor && !wasLocked) {
 wasLocked = true;
 DidLockCursor();
 }
 }
 }