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 ('5f808c050e7b4b73c21029f32d08cf91', -1, 1369237358, 1369237358, '36ea7e5c', -1, 0, 0)

Line : 187
File : sessions.php