Your change to the list of local address books will not take effect until you restart Notes
What happened
You clicked Mail and then clicked Sending and Receiving, and made a change in the Local address books field.
(Notes Basic client users, ; Macintosh OS X users, ), expandedYou can use this field to specify that IBM® Notes® use a different file for your Contacts than the default NAMES.NSF in your data directory, or to add local contacts files (JohnSmithnames.nsf for example). When you add a contact file, the name of the file dispalys in the Directory field when you are selecting names or addresses from a dialog box.
What you can do
Exit Notes® and restart.