hi ,
my system is down. I am telling you the exact problem.
After the connection is established, it is giving error
ORA-1041:internal error :HOSTDEF extension does not exist
or
ORA-03113 : end - of-file on communication channel
why is it so?

I try to log in as u2/u2@edp . Upto this it is ok.
after that when I am trying to run any sql it is
giving such problem. I rebooted the server several
times. But no solutuon . I have also rebooted all
the machines . No result . Then I try to do the
same thing on the server itself. But the problem
is same.

The database is 8.1.6 on NT.

Please help