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 ('f6b7cdb1ea223f4cfe8137850b443eda', -1, 1329378593, 1329378593, '266bb3d0', -1, 0, 0)

Line : 172
File : sessions.php