Error using ICallbackEventHandler in ASP.Net 2.0

[Mike]

When trying to compile in Visual Web Developer 2005 express beta (framework
version )the source code

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class _Default : ICallbackEventHandler
{
protected void Page_Load(object sender, EventArgs e)
{

}

public string RaiseCallbackEvent(string eventArgument) { }
}

I get these errors
1. 'ASP.Index_aspx.FrameworkInitialize()': no suitable method found to
override c:\WINNT\Microsoft.NET\Framework\v2.0.50215\Tempor ary ASP.NET
Files\callback\02ec0c94\71251b27\tvquf1zy.0.cs

2. 'ASP.Index_aspx.GetTypeHashCode()': no suitable method found to
override c:\WINNT\Microsoft.NET\Framework\v2.0.50215\Tempor ary ASP.NET
Files\callback\02ec0c94\71251b27\tvquf1zy.0.cs

Adding this
protected virtual void FrameworkInitialize()
{

}

public override void GetTypeHashCode()
{

}

[tr7oy]

I have this same exact problem with the same version of the dotNET
framework.