Accessing cookies from C#.NET that were created with ASP v3.0

OK, here is the situation.  I have a server that has an old ASP 3.0 application for our computer intranet.  It logs people in, writes some cookies to the machine and everything is good and dandy.

Now, I have an existing application that runs on the same web server that I have pulled those cookie values for years.  Now, I am in the process of switching over to ASP.NET using C# for this application.  However, no matter what I do, I cannot use my .NET application and lookup cookies from ASP 3.0.  I have then entire site converted over to .NET and now all I have to do is take care of the security of the site, which I need to get to those cookies to do.

Here is the code we have:

In ASP 3.0 code, this is what I use to set the cookie:

Response.Cookies("isd281_user_id") = user_id

but if I go to .NET and use:

username = Request.Cookies["isd281_user_id"].Value;

I get the following error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

For some other details, everything is done via a CodeBehind page and I use the following namespace commands:

//Standard classes that need to be loaded
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
//Classes needed for SQL connect
using System.Data;
using System.Data.SqlClient;

Any thoughts or ideas?

Thanks,