Error message

• Notice: Undefined offset: 1 in drupal_settings_initialize() (line 758 of /home/atar8070/public_html/backend/includes/bootstrap.inc).
• Warning: Cannot modify header information - headers already sent by (output started at /home/atar8070/public_html/requisitos.php:15) in drupal_send_headers() (line 1216 of /home/atar8070/public_html/backend/includes/bootstrap.inc).
• PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'system WHERE status = 1 AND bootstrap = 1 AND type = 'module' ORDER BY weight AS' at line 1: SELECT name, filename FROM {system} WHERE status = 1 AND bootstrap = 1 AND type = 'module' ORDER BY weight ASC, name ASC; Array ( ) in system_list() (line 136 of /home/atar8070/public_html/backend/includes/module.inc).