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 ('8d9f428d923e9a9ff97a2e9ae665a8e3', -1, 1328330230, 1328330230, '266bb3e4', -1, 0, 0)

Line : 187
File : sessions.php