First I installed oracle 11i in my PC which has created Oracle homes for 8.0.6 and 9.2 in a different OFA Structure. By default oracle_home in registry is 8.0.6 and application runs fine. When I wanted to connect to other databases, I could not exactly get the place where my tnsnames it is looking and it came with errors (TNSNAMES not found). Hence, I installed another home for 9.2 client and modified the tnsnames within. I am able to connect the external servers and internal applications.

I know that this is not a proper way, but adhoc workaround. If I set system path, my 11i application will not startup or work properly. Hence, I wanted to how oracle is looking the home, whether using registry or system path which has high precedence over another.

Thanks