NullReferenceException: The prefab you want to instantiate is null.
UnityEngine.Object.Instantiate (UnityEngine.Object original, Vector3 position, Quaternion rotation)
RocketLauncher.Fire ()   (at Assets/WeaponScripts/RocketLauncher.js:11)
UnityEngine.Component:BroadcastMessage(String, Object, SendMessageOptions)
UnityEngine.Component:BroadcastMessage(String, Object, SendMessageOptions)
UnityEngine.Component:BroadcastMessage(String)
$:MoveNext() (at Assets/WeaponScripts/AI.js:65)