site will not read cookie

I am having serious problems getting a cookie to work for login on a web app I'm building.  The initial login and cookie creation work - I can see the cookie is created on my system.  However, when I navigate to another page or back to the login page, it behaves as though I'm not logged in, even though I can still see the cookie on my system.  I tried moving the check to the master page's page load, but still having the same issue.  Any ideas or suggestions for what I'm doing wrong would be greatly appreciated.


Thanks!


Code for login page:

Partial Class main_Default
Inherits System.Web.UI.Page

Private Function AuthenticateUser() As Boolean
Dim username As String = usrName.Text
Dim password As String = usrPswd.Text
Dim domain As String = usrDomain.SelectedValue
Dim path As String
...