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 ('aee9e3cd33be39491670c9570fac7a55', -1, 1406138631, 1406138631, '3653e689', 32, 0)

Line : 315
File : sessions.php