SQL info: MySQL Query Error

Time: 2008-10-8 6:31pm
Script: /scenery/citylist.php

SQL: INSERT INTO t_session (sid,uid,islogin,isadmin, updated, sessiondata ) VALUES ('566902','','','', '1223461861', 'a:0:{}')
Error: Duplicate entry '566902' for key 1
Errno.: 1062