TeleTet : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('9ac814d30e1fed781053ca64add5d856', -1, 1414198556, 1414198556, '365b5495', -16, 0, 0)

Line : 189
File : sessions.php