var H00 : Texture2D;
var H10 : Texture2D;
var H20 : Texture2D;
var H30 : Texture2D;
var H40 : Texture2D;
var H50 : Texture2D;
var H60 : Texture2D;
var H70 : Texture2D;

var MAX_HEALTH = 70;
var HEALTH = 70;
function Update()
{
    var g_Health = GameObject.Find("g.Health");
    if(HEALTH > MAX_HEALTH){
    HEALTH = MAX_HEALTH;
    }
    if(HEALTH > 60){
    g_Health.guiTexture.texture = H70;
    }
    else if(HEALTH > 50){
    g_Health.guiTexture.texture = H60;
    }
    else if(HEALTH > 40){
    g_Health.guiTexture.texture = H50;
    }
    else if(HEALTH > 30){
    g_Health.guiTexture.texture = H40;
    }
    else if(HEALTH > 20){
    g_Health.guiTexture.texture = H30;
    }
    else if(HEALTH > 10){
    g_Health.guiTexture.texture = H20;
    }
    else if(HEALTH > 0){
    g_Health.guiTexture.texture = H10;
    }
    else if(HEALTH <= 0){
    g_Health.guiTexture.texture = H00;
       return;
    }
}

from this javascript I get this error NullReferenceException Health.Update () (at Assets/Scripts/Health.js:19) and I have no idea why PLEASE HELP