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 ('9c0ec23d3ff5c59195af1ab1e1355d9a', -1, 1406270650, 1406270650, '36e328a6', 7, 0)

Line : 170
File : sessions.php