Error message

• Notice: Undefined variable: _SESSION in getCurrentSectorNid() (line 347 of /var/www/sofistar-centrale-mobilita/sites/all/themes/centrale/template.php).
• Warning: array_key_exists() expects parameter 2 to be array, null given in getCurrentSectorNid() (line 347 of /var/www/sofistar-centrale-mobilita/sites/all/themes/centrale/template.php).