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 ('9e2c43dacf90932f2a6841c7da33d634', -1, 1257625052, 1257625052, '266bbf58', 4, 0, 0)

Line : 234
File : sessions.php