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 ('7ec29f342ab65c8a016bb7db8c181d0d', -1, 1406608511, 1406608511, '365231c8', 5, 0)

Line : 170
File : sessions.php