phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('e3712f06dc50c61ad811093975d8dc32', -1, 1408807180, 1408807180, '36edf1b1', 11, 0)

Line : 315
File : sessions.php