phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO mex2mex_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('67c451e46c0036780ca8d140e120f677', -1, 1406946264, 1406946264, '32111507', 7, 0)

Line : 170
File : sessions.php