Hi,
The error comes from this :
var gos = Fsm.GetOwnerDefaultTarget(gameObject);
if (gos == null)
{
Debug.LogWarning("missing gameObject: "+ gos.name);
Finish();
}
It is because gets the game object and if there is no object it will return a null.
Then it says if it is null send a warning that the gameobject is missing.... + the gameobject name.
the last part gives the error because there is no object so it can't get the name.
Anyway, so the trigger action does trigger but it does not store the object somehow.
Have you tried setting breakpoints to see what happens?
If you want i can have a look, save the project somewhere and pm me the link.