Object reference not set to an instance when modifying an existing cookie in code behind
<p>In the line "Response.Cookies...", I get an object reference not set to an instance of an object. Is there a way to fix this and use a timer in my ASPX code behind?</p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
{

    object o = new object();

    TimerCallback timercallback = new TimerCallback(StartCallback);

    System.Threading.Timer timer = new Timer(timercallback, o, 0, 50000);



    if (are.WaitOne())
    {
        Response.Redirect("Default.aspx");
    }
}


public void StartCallback(object o)
{
    //Request.Cookies["haspassed?"].Value = "";

    Response.Cookies["haspassed?"].Expires = System.DateTime.Now.AddMonths(-1);

    are.Set();
}
</code></pre>

<p>Thanks</p>
