SQL*Plus ORA-12203: TNS:unable to connect to destination

[Whitebat]

Hello i've got a problem. I'm working with Oracle 8 and SQL*Plus: Release 8.0.4.0.0. I can Connect to my Dba named test in the command prompt and with the Oracle8 Navigator as well. But when I try to connect in Sql Plus this error ORA-12203: TNS:unable to connect to destination occurs and I have no idea why becaus my Oracle sid is definitly set to test. Any idea whats the problem?
Thanks for your help

 

[sem]

Do you have both Sql*Net v.1/2 and Net8 installed? If this is the case you probably connect from different tools via different versions of sql*net and settings for one of them are incorrect. Check both
%ORACLE_HOME%/NET8/ADMIN/TNSNAMES.ORA and
%ORACLE_HOME%/NETWORK/ADMIN/TNSNAMES.ORA files.

Another possible error is in bad listener settings. I'm not completely sure, but it seems to me that Oracle8 Navigator as well as sqldba and contrary to Sql*Plus can connect directly to the local instance, not via tns listener (at least navigator connects to Oracle Lite without any listeners at all).

 

[karluk]

Are you getting any error messages in the SQLNet.log file?

 

[Whitebat]

Well no it seems that i can't connect as internal in sql plus. Maybe because of the version. But all other users can connect now.
Thanks for your help

 

[sem]

The version of your sqlplus doesn't matter (wide-ranging) if ITS Sql*Net settings are correct. If you can connect to that database from another tool you do have correctly installed Oracle client software (though of another version) and probably also have another sqlplus. You may look for it in
%ORACLE_HOME%\bin\plus??w.exe. If you have both 8 and 8i products installed check both homes.