Unity3D getting a NullReferenceException for a split second - unity3d

Question

As the title says. I'm getting a NullReferenceException for a split second, and after that, everything Works just fine. Could anyone tell me why this happens?
Here's my code, error's from line 43:
#pragma strict
//NOTE: Display the health of the enemy that is targetted by the player!
//private var enemyGO : GameObject;
//private var enemyScript : EnemyAI;
var healthText : GUIText;
var myPlayer : Transform;
var myPlayerScript : PlayerScript;
var myPlayerTarget : Transform;
var myPlayerTargetScript : EnemyAI;
function Start () {
myPlayer = GameObject.FindGameObjectWithTag("Player").transform;
myPlayerScript = myPlayer.GetComponent("PlayerScript");
/* if (myPlayerScript.target != null) {
myPlayerTarget = myPlayerScript.target;
myPlayerTarget.GetComponent("EnemyAI");
}*/
// enemyGO = GameObject.Find("Enemy");
// enemyScript = enemyGO.GetComponent("EnemyAI");
}
function FixedUpdate () {
if (myPlayerScript.target != null) {
myPlayerTarget = myPlayerScript.target;
myPlayerTargetScript = myPlayerTarget.GetComponent("EnemyAI");
}
}
function OnGUI () {
if (myPlayerScript.target != null) {
GUI.Label (Rect (((Screen.width / 2) + Screen.width / 3), 16, 250, 20), "EnemyHP: " + (Mathf.Round(myPlayerTargetScript.curHealth)) + " / " + /*(Mathf.Round(*/myPlayerTargetScript.maxHealth/*))*/);
}
}
Thank you :)
EDIT: This doesn't show lines :P
So the error is happening in the GUI.Label... line in my OnGUI function :)

Answer 1

Since you already hold a reference to your EnemyAI script in myPlayerTargetScript you should check this for null in OnGUI
Also don't use FixedUpdate for such things. FixedUpdate belongs to the physics system. Just use Update instead:
#pragma strict
var healthText : GUIText;
var myPlayer : Transform;
var myPlayerScript : PlayerScript;
var myPlayerTarget : Transform;
var myPlayerTargetScript : EnemyAI;
function Start () {
myPlayer = GameObject.FindGameObjectWithTag("Player").transform;
myPlayerScript = myPlayer.GetComponent(PlayerScript);
}
function Update () {
if (myPlayerScript.target != null) {
myPlayerTarget = myPlayerScript.target;
myPlayerTargetScript = myPlayerTarget.GetComponent(EnemyAI);
}
}
function OnGUI () {
if (myPlayerTargetScript != null) {
GUI.Label (Rect (((Screen.width / 2) + Screen.width / 3), 16, 250, 20), "EnemyHP: " + (Mathf.Round(myPlayerTargetScript.curHealth)) + " / " + myPlayerTargetScript.maxHealth);
}
}
ps: You should tidy up your script before posting it here ;)