[Mediawiki-l] MediaWiki 1.1.0: Login Doesn't Stick

[A Chan]

Hi,

I have installed MediaWiki 1.1.0 on a Windows 2000
machine.  Everything works well except for logins. 
After I login, I get the "login successful" message. 
Anytime I click to another page, the page still shows
my IP address, and when I edit a page, the revision is
associated with my IP address.

I have tried both IE 6.0 and Mozilla 1.3.1.

By checking the the "Remember my password across
sessions" upon login I can force logins to stick
across pages.

I have verified that the following three cookies are
set for my site:
-PHPSESSID
-wikidbUserID
-wikidbUserName

Is there an extra configuration step I have missed?  

Thanks for your help!
-Amy