in reply to IE cookies problem
I've run into this before myself and as strange as it sounds, it probably isn't your code, but the user's date, time, and specifically their time zone settings.
I'm not 100% sure about IE7, but with older versions of IE if the expires time was less than 2 hours and the user has their Windows set to the default Pacific time zone and they say live on the East coast IE sees the cookie as already expired and does not set it. Netscape/Mozilla/etc at least set the cookie for the browser session at that point which is why you don't see it with those.
I know it sounds strange, but get a few of the users to tell you their actual timezone and what they have their computer set to and I bet it solves your problem.
Hope this helps...
Frank Wiles <frank@revsys.com>
www.revsys.com