"Could not find a part of the path" exception error with OpenRead()

I'm trying to read multiple files from a client system using script provided by microsoft: http://msdn.microsoft.com/en-us/library/aa478971.aspx , section on uploading multiple files. The only changes I made are in bold font below. I get "Could not find a part of the path" error message when trying to run the following code:
<%@ Import Namespace="System.IO" %>
<%@ Page Language="C#" %>

<script runat="server">

    protected void SubmitButton_Click(Object sender, EventArgs e){
       string filepath = "C:\\Uploads";
       HttpFileCollection uploadedFiles = Request.Files;
   
   ...