Posting data to IIS4

I wonder if anyone can help I use $fp = pfsockopen ($config["remote_URL"],81, &$errno, &$errstr,30); to connect to the remote server using socket 81 this works, how ever as soon as I try sending data to it I get a bad request error. This is what I send: POST VBgateway.asp HTTP/1.0 Accept:*/* User-Agent: VBGateway_socket/1.1 Content-type: application/x-www-form-urlencoded Content-length:451 xml_in= my xml data This is what I receive: HTTP/1.1 400 Bad Request Server: Microsoft-IIS/4.0 Date: Fri, 18 Aug 2000 09:09:52 GMT Content-Type: text/html Content-Length: 87 <html><head><title>Error</title></head><body>The parameter is incorrect. </body></html> Is my header wrong?