Player damage stops working over time

Here is the code for when the enemies attack the player in my simple chase-the-player game:

 var victim : Transform;
 var dieRange = 1.5;
 var explosion : GameObject;
 private var controller : CharacterController;
 
 function Start()
 {
     controller = GetComponent(CharacterController);
 }
 
 function Update()
 {
  var range = Vector3.Distance(victim.position, transform.position);
      
      if (range <= dieRange)
      {
       playerHP.healthPoints=playerHP.healthPoints-0.3;
       
       if(Random.value>0.85)
       {
       Instantiate (explosion, transform.position, transform.rotation);
       }
      }
 }

I'm having two major problems with this so far:

1) The main character takes damage, but after a short amount of time (about five seconds) the health will never go down anymore, so it will be stuck at a value like 47% or 56% and not go down. The enemies continue to chase and surround the player but nothing else happens.

2) I'm getting a recurring error on the command console window saying: "The variable victim of 'damagePlayer' has not been assigned." This is completely untrue because I have declared it both in the script and for each of the AI characters, so I have no idea what is going wrong here. (FIXED)

One of the other scripts I use is the one which modifies the text in the GUI to represent what health the player is at.

 static var healthPoints: int = 100;
 var targetGuiText: GUIText;
 
 function Start () {
 }
 
 function Update () {
  targetGuiText.text = "Health: "+(healthPoints)+"%";
 }

On a lesser note, when my First Person Character jumps, he flies off into the atmosphere and doesn't come back down. I'm using the default FPS character and have not touched the jumping mechanics whatsoever.

Probably worth noting that I'm using the A* Pathfinding Project to make the enemies head towards the player, I'm on a bumpy terrain and I've got eight enemies going at once.

It's working now, thanks for the help!