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 ('9158f0389d570ee385f927950993cc2f', -1, 1411503779, 1411503779, '36a1a6ab', 10, 0)

Line : 315
File : sessions.php