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 ('8d4da8b5350840c651f17e709e548a2a', -1, 1329273174, 1329273174, '266bb3cf', -7, 0, 0)

Line : 187
File : sessions.php