TNS: Could not resolve service name

[Brett]

Hi

Iam trying to connect to an Oracle 8.1.7 database. The initial login is successful and the browser populates successfully but when I open a SQL window and try to execute code it attempts to initialise and then comes back to say:
Could not login in as [login name].
ORA-12154: TNS: Could not resolve service name.

Using a competitors tool works fine but PL/SQL (my prefered tool) does not. Any ideas?

 

[Marco Kalter]

Maybe this is an environment problem. Can you go to Help > About, press the 'Info' button, press the 'Copy all pages' button on this info screen, and paste this text into an e-mail reply?