uncaught exception: YamlHX.get() error, 'session' not found in 'YamlHX'

in file: /var/www/doctorctg.com/deploy/lib/yaml_crate/YamlHX.class.php line 225
#0 /var/www/doctorctg.com/deploy/lib/FlyByNightMixins.class.php(7): yaml_crate_YamlHX->get('session.enable') #1 /var/www/doctorctg.com/deploy/lib/Takeoff.class.php(20): FlyByNightMixins::APP_CONFIG(NULL, 'session.enable') #2 /var/www/doctorctg.com/deploy/index.php(9): Takeoff::main() #3 {main}