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 ('9d1b27e540637e0578b185b53eca9e7d', -1, 1410828608, 1410828608, '36a6088a', -4, 0, 0)

Line : 189
File : sessions.php