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 ('ca54a1239446d1b50fbd5ab4857094c5', -1, 1412245454, 1412245454, '3653ac70', 35, 0)

Line : 315
File : sessions.php