WebException Method not allowed

[sushi]

Hello,
I am trying to use WebClient class's UploadData method for uploading
data to a particular uri. I ahve created a text file say new.txt in the
IISROOT folder. But when I try to upload data to this file using uri
http://localhost/new.txt it gives following exception

Uploading to http://localhost/new.txt ...
The remote server returned an error: (405) Method Not Allowed. at
System.Net.
HttpWebRequest. CheckFinalStatu s()
at System.Net.Http WebRequest.EndG etResponse(IAsy ncResult asyncResult)
at System.Net.Http WebRequest.GetR esponse()
at System.Net.WebC lient.UploadDat a(String address, String method, Byte[]
data
)
at HTTPPostConsole .Class1.Main(St ring[] args) in
f:\httppostcons ole\class1.cs
:line 33

My code is

string uriString;
Console.Write(" \nPlease enter the URI to post data to {for example,
http://www.contoso.com } : ");
uriString = Console.ReadLin e();
// Create a new WebClient instance.
WebClient myWebClient = new WebClient();
Console.WriteLi ne("\nPlease enter the data to be posted to the URI
{0}:",uriString );
string postData = Console.ReadLin e();
myWebClient.Hea ders.Add("Conte nt-Type","applicat ion/x-www-form-urlencoded");

// Apply ASCII Encoding to obtain the string as a byte array.
byte[] byteArray = Encoding.ASCII. GetBytes(postDa ta);
Console.WriteLi ne("Uploading to {0} ...", uriString);

// Upload the input string using the HTTP 1.0 POST method.
byte[] responseArray = myWebClient.Upl oadData(uriStri ng,"POST",byteA rray);

Ths same code works fine if I give uri as www.contoso.com.

How can I solve this problem.