NullReferenceException error

I am fairly new to unity and scripting in c# and I am using unity 5.4.2f2 free version

so I am using the third person controller prefab from the unity standard assets and have added my character model to the prefab and deleted the ethan default model and it works perfect with no errors, I then added it to my “player character prefab” that I made and for some reason I get the following error when I hit play:

NullReferenceException: Object reference not set to an instance of an object

UnityStandardAssets.Characters.ThirdPerson.ThirdPersonCharacter.CheckGroundStatus () (at Assets/Standard Assets/Characters/ThirdPersonCharacter/Scripts/ThirdPersonCharacter.cs:221)

UnityStandardAssets.Characters.ThirdPerson.ThirdPersonCharacter.Move (Vector3 move, Boolean crouch, Boolean jump) (at Assets/Standard Assets/Characters/ThirdPersonCharacter/Scripts/ThirdPersonCharacter.cs:54)

UnityStandardAssets.Characters.ThirdPerson.ThirdPersonUserControl.FixedUpdate () (at Assets/Standard Assets/Characters/ThirdPersonCharacter/Scripts/ThirdPersonUserControl.cs:71)

the script still seems to work as I can run around and jump ect, seem to break when added it to a new prefab I made, could it be because i named the new prefab different? anybody know what I did wrong and how I would fix this?

Could you show us a screenshot of the prefab in the inspector?

The only difference I could see between this prefab I made and the original ThirdPersonController prefab is under the animator it says not initialized on this one, could that be that problem if so how do I fix this?