UnassignedReferenceException on an assigned variable

Hi, i'm very new to Unity (using 4.5) and i'm trying to learn unity 3D. I have this small "game" where I just want to swing an axe to kill spiders. I have created my animation named "AxeSwing" and a small script to trigger the animation when I click my left button. The probleme is that I have an error saying that my variable "attackAnimationClip" has nothing assigned to it. As you can see on the screen shot it is assigned and when I left click the animation trigger and come back to my IdleAxe animation.

Here the script:

Code (CSharp):

1.  
2.  
3. [RequireComponent(typeof(Animation))]
4. public class AttackAnimation : MonoBehaviour {
5.     public AnimationClip attackAnimationClip;
6.       // Update is called once per frame
7.     void Update () {
8.         if (Input.GetMouseButton(0))
9.         {
10.             animation.Play(attackAnimationClip.name);
11.         }
12.         else if (IsAttackFinished)
13.             animation.CrossFade(animation.clip.name);
14.     }
15.  
16.     private bool IsAttackFinished
17.     {
18.         get { return animation[attackAnimationClip.name].time > animation[attackAnimationClip.name].length;  }
19.     }
20. }
21.  

Where did I go wrong ?

 

Does animation.Play("AxeSwing"); work?

 

No but it definitly pointed me in a good direction and was able to debug it. Thanks a lot !!

 

What was the solution? Interested in this fix.