phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'bbfd9f0b148020905b4749253ecd17d4' for key 1

INSERT INTO phpbb2_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('bbfd9f0b148020905b4749253ecd17d4', -1, 1406623193, 1406623193, '36edf59f', 13, 0, 0)

Line : 187
File : sessions.php