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, session_admin) VALUES ('00308b147e6e45440dd3930cc93b3fcb', -1, 1369180864, 1369180864, '36ea2a10', 2, 0, 0)

Line : 187
File : sessions.php