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 ('36f42325a2fddbabffe07e12e14b1c87', -1, 1284008294, 1284008294, '266bbf6f', -10, 0, 0)

Line : 187
File : sessions.php