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 ('c5f263a306f15f437a7b7ba51c117567', -1, 1284037324, 1284037324, '266bbf72', -10, 0, 0)

Line : 187
File : sessions.php