On one system, I'm getting an error message saying that the address book
cannot be opened when a user clicks on the "To..." button in their email.

On another system I'm unable to see my contacts in the address book. When I
try to bind the contacts folder to the Outlook Address book, the "Show
contents in address book" checkbox is grayed out. When I then try to create
an Outlook Address Book, I'm told that the folder already exists and cannot
be created twice. When I then try to view/change/remove the Outlook Address
Book, it is not listed.

How do I proceed from here? I can't add an Outlook Address Book, because I
can't remove the existing (presumably corrupted) one.

Thanks,
Simon