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 ('e151ac5d30edbeaa85d0404a7641c814', -1, 1406351103, 1406351103, '36e10146', 7, 0)

Line : 170
File : sessions.php