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 ('7d00d385e2ea10a15db44ce985b72abc', -1, 1398054937, 1398054937, '321041a8', 5, 0)

Line : 170
File : sessions.php