Well....

The listener is running on a non-default port.

TZ parameter has not been changed on the server - CST6CDT.

Database has been restarted a lot for backups (weekly) and this problem has been consistent.

Listener gets restarted with the DB and registers just fine. From the init.ora:

cms1.local_listener='LISTENER_hpux71'

Anywhere else to look?? I'm tellin' you, this is a puzzler!!

Jody.