phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('e2b83ecbac3aa25e19fbd923619f6d24', -1, 1409631268, 1409631268, '36eac855', 32, 0)

Line : 315
File : sessions.php