Outlook 2003 and Exchange 2003 Setup or Logon Problems

Question: Outlook 2003 Password Dialog Box continuously pops up when trying to setup OL client for Exchange 2003.
-  WinXP Prof SP2 with Oultook and Exchange 2003. When using Outlook, the 'enter network password dialog' comes up over and over (despite the password being correct and saved). I've tried deleting the local mail profile and recreating, have redone the user's password, have checked for spelling errors, have run Outlook's Detect and Repair, have tried both cached and non-cached mode, and recreated the local machine profile .  It works fine on some workstations, but other workstations does not.  Also, if installed, it works as it should with the OWA webmail - only the native Outlook doesn't work.  Additionally, if email is not yet setup on a "problem system", whenever I try to setup the Microsoft Exchange server portion, the password box pops up asking for authentication - but will not accept the proper information - and then cancels the setup after a few tries.  I can setup a "no-mail" or POP account with no problems.   Perhaps a registry hack is available?