这个错在哪里？
错误提示：无法将“<mx:Component>”解析为组件执行。

<?xml version="1.0" encoding="utf-8"?>
<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">
<s:layout>
<s:BasicLayout/>
</s:layout>

<mx:DataGrid x="29" y="303" width="694" height="190" dataProvider="{testData.book}" variableRowHeight="true">
<mx:columns>
<mx:DataGridColumn headerText="Pub Date" dataField="date" width="85" />
<mx:DataGridColumn headerText="Author" dataField="author" width="125"/>
<mx:DataGridColumn headerText="Title" dataField="title">
<mx:itemRenderer>
<mx:Component>
<mx:HBox paddingLeft="2">
<mx:Script>
<![CDATA[
private var _data:Object;
override public function set data( value:Object ) : void {
//super.data = value;
_data = value
var today:Number = (new Date()).time;
var pubDate:Number = Date.parse(data.date);
if( pubDate > today ) setStyle("backgroundColor",0x0);
else setStyle("backgroundColor",0xffffff);
}
override public function get data():Object{
return this._data;
}
]]>
</mx:Script>
</mx:HBox>
</mx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>
</mx:columns>
</mx:DataGrid>
<fx:Declarations> 


</fx:Declarations>
</s:Application>

[解决办法]
fx:Component试试