I succeeded to log onto sql_plus 3.1 using username: scott and password: tiger and left the hoststring blank. But later on when I tried again I failed. The message:
ERROR: ORA-03121: (Cnct err, can't get err txt.  See Servr Msgs & Codes Manual)
ERROR: ORA-09354: (Cnct err, can't get err txt.  See Servr Msgs & Codes Manual)

Help me!!!
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When you tried the 2nd time did you do it with host string.
It appears you need to install/configure sql*net again.
Can you get connected without host string. I assume you
are doing this locally from the server. What is OS and Oracle version?
Look for Your question at:'Your Error here'

ORA-03121 no interface driver connected - function not performed
This is the only what I found:
If you are using an Oracle V6 based application you will get an ORA-03121 when  trying to connect via SQL*Net V2 if you don't use the "tns:" net prefix in the  connect string.  An Oracle V6 based application means that the application is  linked to use ORA6WIN.DLL.  If the application is linked to use ORA7WIN.DLL,  the "tns:" prefix is not needed.      
u can try shutting down oracle database,restarting it and then trying again. this error sometimes comes if the oracle task dies unexpectedly
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Hi Poobalan18,

Reinstalling would help, I suppose some DLLs are missing or have gone corrupt.



Mark GeerlingsDatabase AdministratorCommented:
Don't re-install anything yet.  Please give us some more information.

1. Did you only succeed in logging in to SQL*Plus just one time, and every other attempt failed?

2.  Where is the database, on your PC, on a network server, etc?

3. Which Oracle software do you have installed on the machine you are using SQL*Plus on?  Oracle client software only (which version)?  Also Oracle database software (which version)?
You need to set your $ORACLE_HOME .... your environment does not know where it is ....
PAQed - no points refunded (of 250)

Thanks very much!
amp, ee admin, amp*at*

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