This is my code for downloading text file. But the server.transfer method is not able to resolve that path. It is giving "is not a valid virtual path error"

```
        string filePath = @"D:/BCPResult/Cust_File.t`enter code here`xt";
        Response.ContentType = "text/plain";
        Response.AppendHeader("content-disposition",
           "attachment; filename=" + filePath);
        Response.TransmitFile(Server.MapPath(filePath));
        Response.End();

```

Please guide me...