Base table or view not found: 1146 Table 'drupal.pg_namespace' doesn't exist

I got some errors when I tried to enable Tripal by using drush.

Here is the error message:

WD php: PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'drupal.pg_namespace' doesn't exist: [error] SELECT nspname
FROM pg_namespace
WHERE
has_schema_privilege(nspname, 'USAGE') AND
nspname = 'chado'
;Array (
)
in chado_is_local() (line 157 of /var/www/html/drupal-7.41/sites/all/modules/tripal/tripal_core/api/tripal_core.chado_schema.api.inc). Cannot modify header information - headers already sent by (output started at /usr/local/share/drush/includes/output.inc:37)[warning]
bootstrap.inc:1232
PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'drupal.pg_namespace' doesn't exist:
SELECT nspname
FROM pg_namespace
WHERE
has_schema_privilege(nspname, 'USAGE') AND nspname = 'chado' ;
Array (
)
in chado_is_local() (line 157 of /var/www/html/drupal-7.41/sites/all/modules/tripal/tripal_core/api/tripal_core.chado_schema.api.inc). Drush command terminated abnormally due to an unrecoverable error.

I use CENTOS. I have installed drupal-7, Chado, postgresql(v9.2.14) and download tripal by using drush. http://www.gmod.org/wiki/Tripal_Tutorial_v1.1#Prepare_Drupal_for_Tripal

I followed this tutorial step by step to set my drupal for Installing tripal. but, I still can't enable tripal_core