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 ('f04f3155e7f98d21873b60f1a3f8587a', -1, 1329378591, 1329378591, '266bb3cf', -8, 0, 0)

Line : 172
File : sessions.php