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 ('c432a0993b8ef717e2cbcbad5e2a955e', -1, 1412230966, 1412230966, '36501366', 1, 0)

Line : 315
File : sessions.php