SlickUi in object Won t work

[JoekrJESUS]

Hey. I struggle with a problem. My SlickUI plugin won t work from custom object ? That ' s my code

 

UI.js

var SUI = function (slickUI) {
    this.UI = slickUI;

    this.HPpanel = null;

    this.healthSlider = null;

    this.set();

};

SUI.prototype.set = function() {
    this.healthBar();
};

SUI.prototype.healthBar = function () {
    this.UI.add(this.HPpanel = new this.UI.Element.Panel(10,10,300,60));
    this.HPpanel.add(this.healthSlider = new this.UI.Element.Slider(16,100, 32));
};

game.js  --- I cutted some code from it, cuz file was too long to copy it here, don t mind useless variables

var game = new Phaser.Game(1440, 920, Phaser.AUTO, 'example', { preload: preload, create: create, update: update, render: render });

var tileMap1;

var Mouse, Input, Pointer, colHD, slickUI, SUI;
var img, Player, Enemy;

var panel, button;

var timing = 0;

var Wkey, Skey, Dkey, Akey, Rkey;

function preload() {


    slickUI = game.plugins.add(Phaser.Plugin.SlickUI);
    slickUI.load('ui/kenney.json');

}
function create() {

    game.physics.startSystem(Phaser.Physics.ARCADE);

    Wkey = game.input.keyboard.addKey(Phaser.Keyboard.W);
    Skey = game.input.keyboard.addKey(Phaser.Keyboard.S);
    Dkey = game.input.keyboard.addKey(Phaser.Keyboard.D);
    Akey = game.input.keyboard.addKey(Phaser.Keyboard.A);
    Rkey = game.input.keyboard.addKey(Phaser.Keyboard.R);

   

    colHD = new CollisionsHandler(game.physics.arcade);

    SUI = new SUI(slickUI); // HERE IS MY SLICK UI 

}

function update() {
 
}

function render() {
    //game.debug.geom(Player.aimCircle);
    //console.log(Player.aimCircle);
}

The Error is 

TypeError: Cannot read property 'Panel' of undefined
    at SUI.healthBar (UI.js:17)
    at SUI.set (UI.js:13)
    at new SUI (UI.js:8)
    at Object.create (game.js:60)
    at Phaser.StateManager.loadComplete (phaser.js:31120)
    at Phaser.Loader.finishedLoading (phaser.js:80678)
    at Phaser.Loader.processLoadQueue (phaser.js:80625)
    at Phaser.Loader.asyncComplete (phaser.js:80707)
    at Phaser.Loader.xmlLoadComplete (phaser.js:81619)
    at Phaser.Loader.<anonymous> (phaser.js:81439)