In my application i am uploading files to sharepoint 2007. I am using

using (WebClient webClient = new WebClient())
{
 webClient.Credentials = new NetworkCredential(userName, password);
 webClient.Headers.Add("Content-Type", "application/x-vermeer-urlencoded");
 webClient.Headers.Add("X-Vermeer-Content-Type", "application/x-vermeer-urlencoded");
 String result = Encoding.UTF8.GetString(webClient.UploadData(webUrl + "/_vti_bin/_vti_aut/author.dll","POST", data.ToArray()));
}

the code is running successfully..but for some files it throws exception

The underlying connection was closed: The connection was closed unexpectedly. at System.Net.WebClient.UploadDataInternal(Uri address, String method, Byte[] data, WebRequest& request) at System.Net.WebClient.UploadData(Uri address, String method, Byte[] data)
at System.Net.WebClient.UploadData(String address, String method, Byte[] data)

Any Ideas what I have done wrong?

I am using VS-2008 2.0