Get the colliders transform (?)

I'm not really sure how to put this but i get a NullReferenceException error in the AITrigger script, probably because the collider doesn't have a transform attached to it but i need to access the transform on the same gameobject as the collider is attached to. The question is how? Here is the scripts (Only relevant parts):

AITrigger.cs

     void OnTriggerEnter(Collider other) {
         if (IsEnemy == "Yes") {
             if(other.gameObject.tag == "Friendly" || other.gameObject.tag == "Player") {
                 PlayerPrefs.SetString(gameObject.name, "Yes");
                 AIPath AIPath = GetComponent<AIPath>();
                 sendthis = other.transform;
                 AIPath.SetTarget(sendthis);
             }
         }
         if (IsEnemy == "No") {
             if(other.gameObject.tag == "Enemy") {
                 PlayerPrefs.SetString(gameObject.name, "Yes");
                 AIPath AIPath = GetComponent<AIPath>();
                 sendthis = other.transform;
                 AIPath.SetTarget(sendthis);
             }
         }
     }

AIPath.cs

 public void SetTarget (Transform x) {
         target = x;
 }