Had this problem recently with a windows 2000box running client v5.1.6, talking to a server solaris 2.8 v5.1.6.2.
Somehow the wrong tcp/ip address got associated with the client. Filled in the tcp/ip address and got it resolved. I'll try and dig up the diagnosis messages from support. Involved digging deeply into the database, where I'd never been before. Anyway I ramble. Try filling in the client tcp/pip address manually. Hope this helps.
