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 ('c29012823d59a2a65334b6233bf67f0c', -1, 1369411829, 1369411829, '36ea4337', -1, 0, 0)

Line : 187
File : sessions.php