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 ('3a7b66a5ba170966619874ae6e8913ae', -1, 1328361931, 1328361931, '266bb3ed', -11, 0, 0)

Line : 187
File : sessions.php