SYMPTOMSWhen you want to open a “SQL Plus” session in Oracle Database 10g 10.2.0.1.0 you receive theses erros messages.- ORA-00604: error occurred at recursive SQL level 1- ORA-02248: invalid option for ALTER SESSION CAUSE It's a ORACLE BUG the error occurred only with “Switzerland” regional settings. SOLUTION Edit registry value "NLS_LANG" in key "[HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_OraClient10g_home1]" to "AMERICAN_AMERICA.WE8MSWIN1252"