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 ('4018f1d6f11e0ad979762b659bf22702', -1, 1211133449, 1211133449, '26673f11', 0, 0)

Line : 186
File : sessions.php