phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('9d4860a7197fce52ac09babc78948c12', -1, 1432958712, 1432958712, '36cd73b1', -4, 0, 0)

Line : 189
File : sessions.php