OWA - Folder List will not Appear

From: Angela (anonymous_at_discussions.microsoft.com)
Date: 03/15/04 

Date: Mon, 15 Mar 2004 11:25:41 -0800

Some users located on our Exchange 2003 server accessing
OWA do not see their folder list. The frame instead shows
the following error page...

--------------------------------------------
Bad request
The page that you are looking for might have been removed,
had its name changed, had its content expired, or is
temporarily unavailable.
------------------------

Please try the following:

Make sure that the Web site address displayed in the
address bar of your browser is spelled and formatted
correctly.
If you reached this page by clicking a link, contact the
Web site administrator to alert them that the link is
incorrectly formatted.
Click the Back button or open the home page for this Web
site and look for other links to the information that you
want.
HTTP Error 400 - Request is badly formed.
Internet Information Services (IIS)

------------------------

Technical Information (for support personnel)

Go to Microsoft Product Support Services and perform a
title search for the words HTTP and 400.
Open IIS Help, which is accessible in IIS Manager
(inetmgr), and search for topics titled Web Site Setup,
Web Site Administration, and About Custom Error Messages.
--------------------------------------------

I've searched the MS Knowledge Base articles and only
found this "http://support.microsoft.com/default.aspx?
scid=kb;en-us;831130&Product=exch2003" which references
another hotfix that causes the problem except I have not
installed it. I've tried recreating this in a test
environment but can't seem to figure out the cause for the
error. Only about 30% of the users on this server are
having this problem so far, the rest can see the folder
list with no difficulty. The folder list is fine when
using the locally installed Outlook 2003 client. Also, no
security, application errors on either Exchange or the ISA
server when this occurs. The users can manually
type "https://>/exchange/<userfirstname.userlastna
me>/inbox" and access everything except Rules and Options
within an OWA session.

Any help would be great.