Erro ActionScript no Flex + Java

Programação Java
#1

Pessoal to fazendo um aplicação em Flex com Java e estou tendo o seguinte erro:

TypeError: Error #1009: Não é possível acessar uma propriedade ou um método de uma referência de objeto nula.
at br.com.sectioaurea.prc.view::crudOs/init()[C:\Users\saraiva\workspace\prc\flex_src\br\com\sectioaurea\prc\view\crudOs.mxml:30]
at br.com.sectioaurea.prc.view::crudOs/___crudOs_Application1_creationComplete()[C:\Users\saraiva\workspace\prc\flex_src\br\com\sectioaurea\prc\view\crudOs.mxml:5]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.core::UIComponent/dispatchEvent()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UIComponent.as:12266]
at mx.core::UIComponent/set initialized()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UIComponent.as:1577]
at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:759]
at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072]

segue codigo:

<s:Application xmlns:fx=“http://ns.adobe.com/mxml/2009”
xmlns:s=“library://ns.adobe.com/flex/spark”
xmlns:mx=“library://ns.adobe.com/flex/mx” minWidth=“955” minHeight=“600” backgroundColor="#A49696"
creationComplete=“servico_remoto.listar();init();”>

<fx:Declarations>
	
	<mx:RemoteObject id="servico_remoto" destination="servico">
		<mx:method name="listar" result="onResult(event);" fault="onFault(event);"/>
		<mx:method name="inserir" result="onResultData(event);" fault="onFault(event);"/>
		<mx:method name="alterar" result="onResultData(event);" fault="onFault(event);"/>
		<mx:method name="excluir" result="onResultData(event);" fault="onFault(event);"/>
	</mx:RemoteObject>
	
</fx:Declarations>

<fx:Script>
	<![CDATA[
		import br.com.sectioaurea.prc.entidade.Os;
		import flashx.textLayout.conversion.ConversionType;
		import mx.collections.ArrayCollection;
		import mx.controls.Alert;
		import mx.events.ListEvent;
		import mx.rpc.events.FaultEvent;
		import mx.rpc.events.ResultEvent;
		
		public function init():void{
			dg.addEventListener(ListEvent.CHANGE,selectedItems);
		}
		
		public function onResult(re:ResultEvent):void{
			var data:Object = re.message.body;
			dg.dataProvider = data;
		}
		
		public function onResultData(re:ResultEvent):void{
			servico_remoto.listar();
		}
		
		public function onFault(fault:FaultEvent):void{
			trace("Code: "+fault.fault.faultCode);
			trace("Detail: "+fault.fault.faultDetail);
			trace("String: "+fault.fault.faultString);
		}
		
		public function selectedItems(evt:ListEvent):void{
			inputNumero.text = dg.selectedItem.numero
			//inputDataAbertura.text = dg.selectedItem.data_abertura;
			//inputDataEntrega.text = dg.selectedItem.data_entrega;
			inputTamanhoPF.text = dg.selectedItem.tamanho_pf;
			//inputInicioPrevisto = dg.selectedItem.inicio_previsto;
			//inputFimPrevisto = dg.selectedItem.fim_previsto;
			inputDescricao = dg.selectedItem.descricao;
			//comboStatus.selectedIndex = dg.selectedItem.status;
		}
		
		public function inserir():void{
			Alert.show("Entro no inserir");
			var novaOS:Os = new Os();
			novaOS.numero = inputNumero.text;
			novaOS.data_abertura = new Date(Date.parse(inputDataAbertura.text));
			novaOS.tamanho_pf = parseInt(inputTamanhoPF.text);
			novaOS.data_entrega = new Date(Date.parse(inputDataEntrega.text));
			//novaOS.status = comboStatus.text;
			novaOS.inicio_previsto = new Date(Date.parse(inputInicioPrevisto.text));
			novaOS.fim_previsto = new Date(Date.parse(inputFimPrevisto.text));
			novaOS.descricao = inputDescricao.text;
			servico_remoto.inserir(novaOS);
		}
		
		public function alterar():void{
			Alert.show("Entro no metodo alterar");
		}
		
		public function excluir():void{
			Alert.show("Entro no metodo excluir");
		}
		
		[Bindable]
		public var comboUnidade:ArrayCollection = new ArrayCollection([{label:"Aberto", data:"1"},{label:"Cancelado", data:"2"},{label:"Fechado", data:"3"}]);
		
	]]>
</fx:Script>
#2