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 ('e62380de99b120aa21c78ec4cedad5d8', -1, 1406901215, 1406901215, '36c56c7c', 32, 0)

Line : 315
File : sessions.php