SQLPLus and Linux (Gentoo) - tnsnames problem

Hello
I've installed oracle-instantclient, oracle-skd and oracle-sqlplus. everything works fine, except tnsnames... a can connect to remote database using:

sqlplus
xx/xx@"(description=(address=(host=10.3.1.159)(protocol=tcp)(port=1521))(connect_data=(sid=DVLPBIS)))"

but I'm not able to use tnsnames.
I've created (ok - used my windows tnsnames) TNSNAMES.ORA as below:

DVLPBIS=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.3.1.159)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=DVLPBIS) set TNS_ADMIN to directory in which I have TNSNAMES.ORA

and I've got error: "ORA-12154: TNS:could not resolve the connect identifier specified" (sqlplus xx/xx_at_DVLPBIS)

what's going on ?

I've tried also setting ORACLE_HOME to /usr/lib/oracle/10.2.0.20/client but then I get error:

SP2-1503: Unable to initialize Oracle call interface SP2-0152: ORACLE may not be functioning properly

Has anyone any idea ?
And yes - I haven't got tnsping (it was not delivered it this 3 packages)

-- 
Pozdrawiam
Quosek
qosek_at_o2.pl