Problem with: IndexOutOfRangeException: Array index is out of range.

I have a dialog in the game (sentence per wav file) that I have put in array.

Code (csharp):

1. var sentence : AudioClip[];
2.  
3. function Update ()
4. {
5.  
6.     if (gameVariables.gamestate == 1)
7.    
8.     {
9.         print(sentence.Length);
10.        
11.         dialog ();     
12.         gameVariables.gamestate = 2;   
13.    
14.     }
15.  
16. }
17.  
18. function dialog ()
19.  
20. {
21.  
22.     audio.clip = sentence[0];
23.  
24.     audio.Play();
25.  
26.     yield WaitForSeconds (audio.clip.length);
27.  
28.     audio.clip = sentence[1];
29.  
30.     audio.Play();
31.  
32.     yield WaitForSeconds (audio.clip.length);
33.  
34.     audio.clip = sentence[2];
35.  
36.     audio.Play();
37.  
38.     yield WaitForSeconds (audio.clip.length);
39.  
40. }

At first this works fine. I can hear the sounds etc. But for some reason without me changing (at least that I know) anything it starst to suddenly say: "IndexOutOfRangeException: Array index is out of range.".

I can see in the inspector that there are sounds. If I delete the gameobject that has this script, make a new one, it again works for some time. Couple of times that I run the game. Then stops working. Strange. Any ideas what I'm doing wrong here?

I also added the Debug "print(sentence.Length); " and it gives zero. That's the problem but why is it suddenly giving zero since in the inspector it's clear that there are wav files.

EDIT:

If I call this function from another gameobject it works again. But why? I have no idea.

Code (csharp):

1. var tarina = GameObject.FindWithTag("eventti");
2. tarina.GetComponent(eventsVillage).dialog ();

 

Do you have more than one game object with this script?

All game objects with this script attached has the array filled with at least 3 sounds?

Do you use Awake() and/or Start() to change the values in this array (or any other function for that matter)?