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 ('43ca52d99060b036555e9db7d883f513', -1, 1414210509, 1414210509, '36594f21', 11, 0)

Line : 315
File : sessions.php