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 ('f3c6e01922bbefacfcea772e1b0b7fb1', -1, 1397845856, 1397845856, '36cca31a', 7, 0)

Line : 170
File : sessions.php