This 405 error code looks like a standard HTTP error code. For a list see http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html.
in reply to Net::Trackback question
405 is a 'method not allowed'. I'd recommend dumping your network traffic (using tools like tcpdump, ethereal) to see what exactly is going on. If you don't know HTTP, you'll learn a lot in the process.
PS: when I try the above code right now I get an 404 error (probably because the http://myblog.blogs.com/2005/09/Just-testing.html was removed)