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 ('280dffe7d44e172ab42a231f1b76ac4f', -1, 1328330341, 1328330341, '266bb3e5', -7, 0, 0)

Line : 187
File : sessions.php