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 ('1ab0849d0a46e6ec0bd5b24a1937b031', -1, 1398299974, 1398299974, 'ae81a3b7', 7, 0)

Line : 170
File : sessions.php