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 ('4152ae03ae4759d3ed38c1c02904788c', -1, 1406276629, 1406276629, '3653f158', 7, 0)

Line : 170
File : sessions.php