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) VALUES ('4536fa8f6d9602f94e156f4885144e63', -1, 1409701269, 1409701269, '365a2a9c', 0, 0)

Line : 158
File : sessions.php