"Could not log on as"

[Maria Davidenko]

Hi all!
I have 2 ORACLE_HOME directories at my computer(Oracle clients 8i and 10g).Since I changed it via Preferences > Oracle > Connections > Oracle Home I can not connect to ORACLE at all and every time get the message "Could not log on as schema_name" . I can connect ORACLE using sqlplus.The version of PL/SQL Developer installed is 6-th.

Please,help me to solve the problemm!
Thanks,

Mariya.

 

[Marco Kalter]

I'm not familiar with the error message "Could not log on as schema_name". Can you let me know the exact message? Is there any ORA/TNS error code?