New Session On Page Inside A Frameset

I have been using session variables to pass a user name from one ASP
page to another inside framesets for 9 months and it stopped working
this week. I have made no code changes but there was a "security
update" installed on the server a few days ago but I can't find out
exactly what it was.

In the research I have done I found many articles on the subject of
session variables in ASP pages inside framesets. From what I read a
new session will be started every time a new ASP page is accessed
until a session variable is set, once a session variable is set the
session will stay the same from page to page, even when using frames.
It is possible to start a session by setting a session variable in the
global.asa file.

My page 1 sets the session variable "username", this page calls page 2
which then uses the "username" variable. This still works on the two
test servers I have where no upgrades of any kind have been done. I
changed the code to display the Session.SessionID in both page 1 and
page 2. On my test systems I get the same session id number, on my
production system I get two different session id numbers and when I
turn on prompting for all cookies I get the session cookie prompt when
the second page is called. The two test systems are on the same
network as my workstation, the production machine on the internet at a
hosting site.

I have cookies enabled in my browser, session state is enabled in IIS
and there are no special characters in the domain name of the web
site. I did not have a global.asa file so I added one and I set a
session variable in the global.asa just to get the session started.
What I find interesting is if I display the variable I set in the
global.asa file I can see it on both page 1 and page 2 but on page 2
I can't see the variables set on page 1. I am completely stumped.
Does anyone have any idea what I can do to get this working again? .....