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 ('c5ce7b9070b308d1d127cf2ec39a5c8b', -1, 1280562262, 1280562262, '266bbf51', -1, 0, 0)

Line : 187
File : sessions.php