hi evryone , i am encounter with a small problem i want to make a 3d rtl text animation with papervision this code generet a problem to this :

[Fault] exception, information=TypeError: Error #1009: Cannot access a property or method of a null object reference. but when using a english text this error dont genereta my code :

package {
import flash.display.Sprite;
import flash.events.Event;

import org.papervision3d.scenes.Scene3D
import org.papervision3d.view.Viewport3D
import org.papervision3d.cameras.Camera3D
import org.papervision3d.render.BasicRenderEngine
import org.papervision3d.typography.Font3D
import org.papervision3d.typography.fonts.HelveticaBold
import org.papervision3d.typography.Text3D
import org.papervision3d.materials.special.Letter3DMaterial
import flash.text.engine.FontDescription
import flash.text.engine.ElementFormat
import flash.text.engine.TextElement
import flash.text.engine.TextBlock
import flash.text.engine.TextLine


/**
 * ...
 * @author vahid
 */
public class Main extends Sprite 
{
	private var fd:FontDescription
	private var ef:ElementFormat
	private var te:TextElement		
	protected var st:String;

	private var scene:Scene3D
	private var view:Viewport3D
	private var camera:Camera3D
	private var render:BasicRenderEngine
	private var vpWidth:Number = stage.stageWidth;
	private var vpHeight:Number = stage.stageHeight;
	private var text3d:Text3D 
	private var font3d:Font3D 
	//private var font:HelveticaBold
	private var textMaterial:Letter3DMaterial 
	private var text:String 


	public function Main():void {
		if (stage)
			init();
		else
			addEventListener(Event.ADDED_TO_STAGE, init);
	}

	private function init(e:Event = null):void {
		removeEventListener(Event.ADDED_TO_STAGE, init);
		// rtl block 
		fd = new FontDescription ()					
		ef = new ElementFormat (fd)			
		te = new TextElement ("?????? ?????? ???? ?????? ?? papervision", ef)

		text = te.text		
		//3d block

		scene = new Scene3D ()
		view = new Viewport3D (vpWidth,vpHeight,true,true,false,false)
		camera = new Camera3D ()
		render = new BasicRenderEngine()
		addChild (view)
		this.addEventListener (Event.ENTER_FRAME , renderThis)
		textMaterial = new Letter3DMaterial(0xFF0000,1)
		font3d = new HelveticaBold()
		text3d = new Text3D (text, font3d, textMaterial)
		scene.addChild (text3d)

	}


	protected function renderThis(e:Event):void 
	{
		text3d.rotationY +=5
		render.renderScene(scene,camera,view)
	}

}

} i am using flashdevelop. please help me thank's