Mailbox can not be removed

One of my users who has an account on our Exchange server and uses Outlook
2003 asked me how she can move e-mails from an account that is being
terminated at the university she came from before she worked here.

She found instructions at their website and I followed them to add another
mailbox in her Outlook 2003 profile. She moved the messages from that account
to her Exchange account here by dragging them.

When she was finished, I ran the Mail applet in Control Panel and removed
the additional mailbox. However, when she subsequently ran Outlook, the
mailbox was still there, but when you click on it you see an error "The set
of folders could not be opened."

Now there is a sort of Catch-22. You can't see it in the Mail applet but you
can't click on it to delete it or do anything with it.

Any advice would be appreciated.

Thanks,
Don