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 ('eeb2c87c81f4c5de3f15631c94fff770', -1, 1257629176, 1257629176, '266bbf55', 7, 0, 0)

Line : 234
File : sessions.php