instant client RH EL 4.4 sqlplus

Hello, Am trying to configure instant client 10_2 on RH EL 4.4. So have set LD_LIBRARY_PATH, PATH and ORACLE_HOME to the dir where the unzipped instant client lives. However cannot seem to connect to remote DB using sqlplus like so: sqlplus user/password@IPAddress:1521/F RED Error 6 initializing SQL*Plus