Hi:

I use loader in ext:window. I get JavaScript runtime error: Unable to get property 'load' of undefined or null reference. the debug stopped in the the compiled line: loader.load(Ext.applyIf({disableCaching:disableCac hing},loader.lastOptions||{}));},load:function(con fig){this.getLoader().load(config);},clearContent: function(){if(this.iframe&&this.iframe.dom){var me=this,doc,prop;this.iframe.un("load",this.getLoa der().afterIFrameLoad,this);try{doc=me.getDoc();if (doc){if(!Ext.isIE){Ext.EventManager.removeAll(doc );}
for(prop in doc){if(doc.hasOwnProperty&&doc.hasOwnProperty(pro p)){delete doc[prop];}}}

Can you tell what's wrong with it?

Here is my code:
 <ext:Window ID="winDocTypeKeywordList" runat="server" Title="Window" Frame="true"
        Width="830" ConstrainHeader="true" Height="560" Maximizable="true" Closable="true"
        Resizable="true" Modal="true" Hidden="true">
        <Loader Url="../DocTypeKeywordList.aspx" Mode="Frame"   runat="server" ID="LdKeyword"  >
            <Params>
                <ext:Parameter Name="DocTypeID" Mode="Raw" Value="0">
                </ext:Parameter>
            </Params>
        </Loader>
        <Listeners>
            <Hide Handler="this.clearContent();" />
        </Listeners>
    </ext:Window>
Thanks.
Holly