I was using MS ODBC Driver for Oracle (MSORCL10.DLL) against Oracle7 & Oracle8 databases. When I installed Oracle8i database (8.1.6) I was using the same code but unable to connect: Error SQLSTATE S100 "Error
attempting to login". I found on Oracle Metalink Support that S100 error happens with Oracle7 driver version 1 and ODBC Driver Manager
(ODBC32.DLL) version2. Solution offered there was simple: upgrade
driver.

Therefore, I concluded I need to upgrade my MS ODBC Driver for
Oracle (MSORCL10.DLL), knowing that next generation driver (MSORCL32.DLL) is available since 1998. However I was unable to connect using MS ODBC for Oracle (MSORCL32.DLL): Error SQLSTATE NA000 "Error while trying to retrieve text for error ORA-00000". What's wrong ?

By the way, ORA-00000 means normal, successful operation. No errors.

I was able to connect successfully to Oracle8 or Oracle8i databases using Oracle8 client networking components, but as soon I switched to Oracle8i client networking components I can't connect to anything.

Seems to me that the problem between ODBC Driver and client networking software, but it's possible that I'm missing something simple since I can't believe that Microsoft driver is incompatible with Oracle8i.

Any thoughts would be appreciated.