I would not have believed it but that was the issue. I solved it by adding names.default_domain to the sqlnet.ora file (it was previously null) and then adding the default_domain string to the db_link string in the sys.aq$_agent definition of the recipients part of the message_properties. My great thanks to you. I'm a little incredulous that db links, sqlplus, ... everything else worked fine, but AQ wouldn't even raise the whimper of an error message. Oh well, just another day in Oracle land.