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 ('75dd5bdbf8b3806e35c7b88d8b9cc77b', -1, 1414152044, 1414152044, '36a60f98', 35, 0)

Line : 315
File : sessions.php