Lotus Notes using old address

One of the users in my company is having the following trouble:
The user changed the internet address of a personal contact in the personal address book located on the local machine. When the user tries to use the type ahead feature in the To: field, it is finding the contact, but is associating it with the older address.
The Client is 5.0.7 and I noticed that the address book is R4, tried to refresh design and still R4. Then tried to recreate the personal address book and copy all the entries from the old book into the new book, closed Notes and renamed the newer file to the names.nsf. After I did that, opening Notes I get the error, names.nsf can not be found. Any help would be appreciated.