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 ('69528eafd537db9740704031d2cf67d3', -1, 1397696999, 1397696999, '36e305ea', 7, 0)

Line : 170
File : sessions.php