No reminders – cannot locate recurrence

Microsoft Office Outlook – v2003
After I launch Outlook the following message comes up:
There was a problem reading one or more of your reminders. Some reminders may not appear. Cannot locate recurrence information for this appointment.
OK
When you click on OK then you get a system message stating ‘the operation failed’
All items on the calendar have no reminders – doesn’t matter whether the items are recurring or not.
H E L P
Mary