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, session_admin) VALUES ('e8cc74f931b7d6315aa4e65db48b9bc7', -1, 1210606098, 1210606098, '26673f10', 0, 0, 0)

Line : 173
File : sessions.php