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 ('af3ce7c432afe27149e14d2a5a6d4a54', -1, 1397994356, 1397994356, '36eb24a4', 10, 0)

Line : 158
File : sessions.php