I've just filed another bug report upstream at:
Turns out I cannot access a gal (global access list - ie address book)
via ldap on a Zimbra 7.1.3 server with kap where Thunderbird has no
trouble and I am able to access an address book on a Zimbra 5.0.10
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.