Samba 2.2.4 on Solaris 8 - WINS Entry does not refresh

List:

This server is a domain member server and uses NT authentication
(Security=Domain). Somehow, since upgrading to Solaris 8 it is unable to
maintain its WINS registration on the domain's WINS server, that on a daily
bases, we have to cycle nmbd and smbd.

Any ideas where the break may be?