Solving "The underlying connection was closed: An unexpected error occurred on a send." (Webservices)

Jan Thielen (MVP) gives a solution to the problem of sporadic errors of type "The underlying connection was closed".

In essence, you need to add the following code to your Webreference's Reference.cs file:

protected override System.Net.WebRequest GetWebRequest(Uri uri)
{ 
  System.Net.HttpWebRequest webRequest = 
    (System.Net.HttpWebRequest) base.GetWebRequest(uri); 
  webRequest.KeepAlive = false; return webRequest;
}