Symptoms
Users or Contacts appear blank in both the Address list and the Sender and Receiver column of the mailbox.
This problem may be limited to one user or it may affect multiple users.
Characteristics of this problem are such that OfficeTalk will not display the username in the titlebar; contacts, users or both; appear blank in address list; and the sender and receiver column of mailboxes may be blank on certain messages.
Cause
This behaviour will occur if, for some reason, the name style has become corrupt.
Resolution
To resolve, OfficeTalk will need to be forced to recreate the user and contact name styles.
Detail
http://softalkltd.com/support/faq_item.asp?area=21&id=879