Model is a singleton. Use Model.instance instead.

Model.as

package Model.Modelo
{
	import mx.collections.ArrayCollection;
	
	[Bindable]
	public class AppModel 
	{
		private static var _instance:AppModel;
		
		
		public function AppModel()
		{
			if( _instance != null )
			{
				throw new Error( "Model is a singleton. Use Model.instance instead." );
			}
			_instance = this;
		}
		
		public static function get instance():AppModel
		{
			if(_instance == null){
				_instance = new AppModel();
			}
			return _instance;
		}
		public static var prodbusiness:*;
		public static var prodclick:*;
		public static var modifyAd:*;
		public static var vo:*;
		public static var voAd:*;
		public static var voCat:*;
		public static var voDist:*;
		public static var vo4:*;
		public static var vo5:*;
		public static var vo6:*;
		public static var vo7:*;
		public static var vo8:*;
		public static var listbus:*;
		public static var listbusaccceptbusiness:*;
		public static var persondetail:*;
		public static var employerdetail:*;
		public static var UsuarioDestino:String; 
		
		public static var UsuarioOrigen:String;
		
		public static var CuentaBancaria:String;
		
		public static var Asunto:String;
		
		public static var Mensaje:String;
		
		public static var Sentby:String;
		
		public static var Detalles:*;
		
		public var indice:int = 0;
		
		public var usuario:String = AppModel.nombre_usuario;
		public var roles:String = AppModel.privilegiado;
		public var busninessname:String = AppModel.personId;
		
		public static var productslist:ArrayCollection = new ArrayCollection(); 
		public static var available:ArrayCollection = new ArrayCollection();
		
		public static var detalleproducto:ArrayCollection = new ArrayCollection();
		
		public static var administrator:String = "Administrator.swf";
		public static var user:String = "User.swf";
		public static var school:String = "School.swf";

		
		
		
		public static var privilegiado:String = "";
		public static var nombre_usuario:String = "";
		public static var personId:String = "";
	}
}