Linking to specific page in rss feed in flex 4.6

In flex 4.6 i'm showing an rss feed of giantbomb. I'm filling up a datagrid with this information but I want to link each item to his specific page. I created a function for it but when I click nothing is happening. What i'm a doing wrong?

<?xml version="1.0" encoding="utf-8"?>
<mx:ViewStack xmlns:fx="http://ift.tt/rYUnH9" 
              xmlns:s="library://ns.adobe.com/flex/spark" 
              xmlns:mx="library://ns.adobe.com/flex/mx"
              width="100%" height="99%"
              backgroundColor="#e9e9e9" contentBackgroundColor="#e9e9e9"
              paddingTop="25" >
    <fx:Script>
        <![CDATA[
        public function openRssAt(index:int):void {
            var url:String = rssFeed.lastResult.rss.channel.item.link;

            navigateToURL(new URLRequest(url), "_blank");
        }
        ]]>
    </fx:Script>
    <fx:Declarations>
        <s:HTTPService
            showBusyCursor="true" id="rssFeed" resultFormat="object"
            url="http://ift.tt/1m9CIQW"/>
        <s:HTTPService
            showBusyCursor="true" id="rssFeed2" resultFormat="object"
            url="http://ift.tt/1ktgCOm"/>

    </fx:Declarations>
    <!-- MASTER -->
    <s:NavigatorContent width="100%" height="100%">
        <s:ButtonBar x="154" y="351"/>
        <mx:TabNavigator x="0" y="-88" width="302" height="45">
            <s:NavigatorContent width="100%" height="100%" label="New releases">

                    <s:DataGrid width="100%" height="100%" id="rssfeed" gridClick="openRssAt(event.rowIndex)"
                                dataProvider="{rssFeed.lastResult.rss.channel.item}"
                                creationComplete="rssFeed.send()">
                        <s:columns>
                            <s:ArrayList>

                                <s:GridColumn dataField="title" headerText="Titel"/>

                            </s:ArrayList>
                        </s:columns>
                    </s:DataGrid>

            </s:NavigatorContent>
            <s:NavigatorContent width="100%" height="100%" label="News">



                    <s:DataGrid width="100%" height="100%" id="rssfeed2" gridClick="openRssAt(event.rowIndex)"
                                dataProvider="{rssFeed2.lastResult.rss.channel.item}"
                                creationComplete="rssFeed2.send()">
                        <s:columns>
                            <s:ArrayList>

                                <s:GridColumn dataField="title" headerText="Titel"/>

                            </s:ArrayList>
                        </s:columns>
                    </s:DataGrid>


            </s:NavigatorContent>
</mx:TabNavigator>
        </s:NavigatorContent>
</mx:ViewStack>