As we discovered , it was the problem with multiple homes. I changed the default home to the Personal edition Oracle8i and the database is getting connected from the that directory.

I am trying to use data blocks in form to base the table in the oracle8i edition. I must mention that forms and Reports6i was installed on another directory which apparently seem to be having its own HOME which is also reflected in the registry. But when i try to use Form builder to connect to the database which is in another HOME gives me the TNS:Could not resolve service name. I am new to this. Could you help me in resolving this problem.

MUCH THANKS.