It works for me. Here is my test case.
Example Parent Page
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<script runat="server">
[DirectMethod]
public void Redirect(string url)
{
X.Redirect(url);
}
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Ext.Net Example</title>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
<ext:Panel runat="server">
<AutoLoad Mode="IFrame" Url="Test.aspx" />
</ext:Panel>
</form>
</body>
</html>
Example Child Page
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
Ext.Net.X.Js.Call("parent.Ext.net.DirectMethods.Redirect", "http://google.com");
}
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Ext.Net Example</title>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
</form>
</body>
</html>