phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO mex2mex_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('fe948f32cd06d21040bec5186ab8f692', -1, 1397836472, 1397836472, '36c55719', 5, 0)

Line : 170
File : sessions.php