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 ('e3f06139d3f3e082e94cc05afc674d25', -1, 1414205027, 1414205027, '36a60f98', 20, 0)

Line : 315
File : sessions.php