I have a number of users on Windows XP SP3 and Office 2007 SP2 that have connected a SharePoint (MOSS) 2007 calendar to their Outlook.  Several of these users are experiencing intermittent login prompts throughout the day to connect to SharePoint from Outlook.  All affected users have Full Control rights to the SharePoint list and the SharePoint site is set up as a Trusted Site with "Automatic logon with current username and password" enabled.  I feel I have exhausted all options.  I, as the site administrator, am unable to duplicate the problem on my own machine with the same configuration.  I am not even experiencing a login prompt when I first launch Outlook, which is to me the expected behavior.

Does anybody out there have a reciprocal experience or any additional information as to how to resolve the problem?

Thanks in advance