phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_datingforum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('dfe89c0c417b9012408a3c1325b0ec12', -1, 1406123832, 1406123832, '36c68c82', 9, 0)

Line : 174
File : sessions.php