Symfony 2 Log out error

I am trying this links from 7 days but still today I am getting errors may I know what the wrong with this login page?

Why I am not getting log out after login?

http://ift.tt/1uOgZCv

My Code

# app/config/security.yml
security:
encoders:
    Acme\MainBundle\Entity\User: plaintext

role_hierarchy:
    ROLE_ADMIN:       ROLE_USER
    ROLE_SUPER_ADMIN: [ ROLE_ADMIN, ROLE_ALLOWED_TO_SWITCH ]

providers:
    administrators:
        entity: { class: AcmeMainBundle:User, property: username }

firewalls:
    admin_area:
#            pattern:    ^/admin
        http_basic: ~
        logout:
            path:   /logout
            target: /

access_control:
    - { path: ^/admin, roles: IS_AUTHENTICATED_FULLY }

I can Login with this code after 7 days of work but can't log out may I know where I am wrong?