phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_cmnsessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('9673157e62e5b828a8db07cb5d9f8329', -1, 1246732604, 1246732604, '26673f3e', 0, 0, 0)

Line : 172
File : sessions.php