发内容时返回这个错误 error: (404) 是什么原因？

linyansong

The remote server returned an error: (404) Not Found.

待进行错误分析的返回头：
HTTP/1.1 404 Not Found
Date:Tue, 06 Apr 2010 23:53:37 GMT
Server:Apache/2.2.3 (Red Hat)
Content-Length:-1
Connection:close
Content-Type:text/html; charset=iso-8859-1