OCIEnvCreate failed to create environment handle after installing oracle_fdw

I have installed oracle_fdw successfully. After I create extension oracle_fdw and foreign table it shows the following error. Is this a server configuration problem? --env Oracle : 10.2.0.1 PostgreSQL: 9.1.3 --create foreign server skytf=# CREATE SERVER oracle_srv skytf-# FOREIGN DATA WRAPPER oracle_fdw skytf-# OPTIONS (dbserver '//192.168.1.30:1521/MANUA'); CREATE SERVER skytf=# grant usage on foreign server oracle_srv to skytf; GRANT --create mapping user skytf=# CREATE USER MAPPING FOR skytf skytf-# SERVER oracle_srv skytf-# OPTIONS (user 'read_only', password 'read_only'); CREATE USER MAPPING --create foreign table skytf=# CREATE FOREIGN TABLE ft_test_1 ( skytf(# id integer, skytf(# name character varying(20) skytf(# ) SERVER oracle_srv skytf-# OPTIONS (schema 'ocp', table 'test_1'); CREATE FOREIGN TABLE skytf=# \c skytf skytf skytf=> select * from ft_test_1; ERROR: error connecting to Oracle: OCIEnvCreate failed to create environment handle DETAIL: