Cannot access other user folder.

As of few weeks back we cannot set up access to other users folder.

We can add their mailbox in the folder view but when trying to access them
we get the error "Access denided". The ones set up while back work just
fine. The new set up do not. We also get "Access denided" on these when
trying to use "Send as". The permissions seem to be set up exatly the same
as we used to do this in the past. We use Outlook 2003 with the Exchange
2003.
Any help would be appreciated.

BTW. The small group of Domain Admis does not have any of these issues. Onlt
the regular Outlook users.