I am having similar problem.
I have developed web service, which is called by my application for checking
updates. If update is found then path of the related cab file is returned to
application. In application, I am programmatically downloading files on
Pocket PC by following code.

This code works fine when I configure my web service locally (local IIS). I
am able to download cab file but in case of live address this code gives
“HTTP 403 forbidden” error.

When I try to open the same cab file from pocket pc’s IE then it can be
downloaded via IE on Pocket PC, but when I try to download it
programmatically it gives error.

   'Used for creating Request.
       Dim LOC_Req As HttpWebRequest
       Dim LOC_Resp As HttpWebResponse

       ' Retrieve response stream
       Dim LOC_RespStream As Stream
       'Used Create local cab file
       Dim LOC_Wrtr As FileStream
       Dim LOC_BytesRead As Integer = 0
       ' Allocate byte buffer to hold stream contents
       Dim LOC_InData(4095) As Byte
       Try
           'Creating request
           LOC_Req = CType(WebRequest.Create(DownloadUrl), HttpWebRequest)
           'Set http-request's method to "GET"
           LOC_Req.Method = "GET"
           'Get Response.
           LOC_Resp = CType(LOC_Req.GetResponse(), HttpWebResponse)
           'Check if available space on device is less than or equal to
size of cab file.
           'Get Response's stream.
           LOC_RespStream = LOC_Resp.GetResponseStream()
           'Create a file.
           LOC_Wrtr = New FileStream(LocalFile, FileMode.Create)
           'loop through response stream reading each data block
           'and writing to the local file
 LOC_BytesRead = LOC_RespStream.Read(LOC_InData, 0, LOC_InData.Length)
           While LOC_BytesRead > 0
               LOC_Wrtr.Write(LOC_InData, 0, LOC_BytesRead)
               LOC_BytesRead = LOC_RespStream.Read(LOC_InData, 0,
LOC_InData.Length)
           End While
       Catch Ex As Exception
           'Set object of Exception. Calling application will have
           'read only access to this object.
           MsgBox(Ex.Message)
       Finally
           LOC_RespStream.Flush()
           'Closing Response stream
           LOC_RespStream.Close()
           'Closing writer stream
           LOC_Wrtr.Close()
       End Try
   End Sub 'DownloadFileBinary

Please guide me.

I think what is need is something like this in the web.config file if you
want to use Get or Post

system.web>
   <webServices>
       <protocols>
           <add name="HttpPost" />
           <add name="HttpGet" />
       </protocols>
   </webServices>
</system.web>