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 ('14b36d6992174ff046a7e0ed43153212', -1, 1397917806, 1397917806, '36d38ab4', 10, 0)

Line : 158
File : sessions.php