I have installed Designer 6.0, Developer 6.0 and Oracle 8.1.6 EE (administrator version of OEM) on my Windows 2000 machine. When trying to access Developer I get the TNS names not found error message. I've found 8 TNSNAMES files on my machine. I've changed the data via Easy Config and NET 8 Configuration Assistant. I can't access the OEM console or Developer. I can use SQL*Plus version 3 to access the database but not SQL*PLUS version 8. Any ideas would be appreciated.
Why do I have to use both Easy Config and the Network Administration tool in OEM?

Thanks