HTTP error codes and their meanings
'404' means: Not Found.
'401' is an unauthorized request.
'402' is a payment required notice.
'403' means: strictly forbidden.
'408' means: request time-out.
'411' means: information
'500' is an internal server error.
'501' is a non-implemented server-side facility.
'503' is a temporarily overloaded server.
For more information (411) on the Web, swing by W3.ORG