New Unity GUI buttons take three to six presses to work and why??

Hi chaps,

First time out with new Unity GUI.
Not impressed so far.
Yes, easier to set up BUT no, doesn’t really work and I can’t figure out why.

So I’ve got some buttons set up as per the docs and they only work after between three and six goes at clicking on them. I can’t figure it out. Normally either it works or it doesn’t.

Here is the script attached according to the docs:

using UnityEngine;
using System.Collections;

public class ChangeScene : MonoBehaviour {


    public void ChangeToScene (string sceneToChangeTo) {
        Application.LoadLevel (sceneToChangeTo);
  
    }
  
    // Update is called once per frame
    void Update () {
  
    }
}

So why DOES it take three to six clicks to get the buttons to work in a web build and now isn’t working at all in the Editor in spite of working fine for days and I have changed nothing!
Demo here: http://hayesdavies.co.uk//Secret EscapeDec.html

All help gratefully received. Thanks.

And now there’s another Fatal Error…

Anybody know what it means?
Thanks guys.

For anyone searching, the answer to the button problem was eventually found here: