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 ('77fc37319c5b43df0df014f969daba96', -1, 1406229716, 1406229716, '3653e629', 10, 0)

Line : 315
File : sessions.php