flex4模块中有DataGrid加载时报错解决方案

<?xml version="1.0" encoding="utf-8"?>
<mx:HBox xmlns:fx="http://ns.adobe.com/mxml/2009" 
         xmlns:s="library://ns.adobe.com/flex/spark" 
         xmlns:mx="library://ns.adobe.com/flex/mx" width="100%" height="100%"
         label="基本信息"
          backgroundAlpha="0.0" contentBackgroundAlpha="0.0"
          creationComplete="init()"
          >
    <fx:Script>
        <![CDATA[
            import com.whlhy.lhymis.Modules.GoodsDGMD;
            
            import mx.collections.ArrayCollection;
            import mx.controls.Alert;
            import mx.rpc.events.ResultEvent;
            
            public var selectedNode:XML;
            
            public var GDGMD:GoodsDGMD;
            public function init():void{
//                goods.findAllGoodsFromSD();
//                goods.addEventListener(ResultEvent.RESULT,goods_result);
//                module.loadModule("BIV_GoodsDG.swf");
//                Alert.show("a");
            }
            
[color=#FF0000]            public function treeChange(e:Event):void{
                selectedNode=Tree(e.target).selectedItem as XML;
                if(selectedNode.@label == "基本信息"){
                    displayModule("com/whlhy/lhymis/Modules/GoodsDGMD.swf");
                }else{
                    displayModule("com/whlhy/lhymis/Modules/WelcomeMD.swf");
                }
            }

            private function displayModule(moduleUrl:String):void{
                var url:String=module.url;
                if(url==moduleUrl) return;
                if(url!=null) 
                    module.unloadModule();
                module.url=moduleUrl;
            }[/color]
        ]]>
    </fx:Script>
    <fx:Declarations>
        <!-- 将非可视元素（例如服务、值对象）放在此处 -->
    <mx:RemoteObject id="goods" destination="goodsService" endpoint="http://localhost:8080/LHYMIS/messagebroker/amf" />
        
        <fx:XMLList id="treeData">
                <node label="原料信息">
                    <node label="基本信息"/>
                    <node label="等待添加"/>
                    <node label="等待添加"/>
                </node>
                <node label="自配料信息">
                    <node label="自配料信息"/>
                    <node label="等待添加"/>
                    <node label="等待添加"/>
                </node>
                <node label="菜品信息">
                    <node label="菜品信息"/>
                    <node label="等待添加"/>
                </node>
                <node label="等待添加"/>
                <node label="等待添加"/>
        </fx:XMLList>
        
    </fx:Declarations>
    <mx:HDividedBox width="100%" height="100%" backgroundAlpha="0.0" contentBackgroundAlpha="0.0">
        <s:BorderContainer width="20%" height="100%" backgroundAlpha="0.51" contentBackgroundAlpha="0.53">            
    <mx:Tree width="100%" height="100%" contentBackgroundAlpha="0.0" labelField="@label"
             showRoot="false" dataProvider="{treeData}" change="treeChange(event)">    
    </mx:Tree>
            
        </s:BorderContainer >
        <s:BorderContainer width="100%" height="100%">
        <mx:ModuleLoader id="module"  ready="init()" height="100%"  width="100%" url="com/whlhy/lhymis/Modules/WelcomeMD.swf" />
        </s:BorderContainer>
    </mx:HDividedBox>

</mx:HBox>