System.IO.DirectoryNotFoundException: Could not find a part of the path 'D:\SavingTextfile\sampletext_44.txt'.

HI,

     I am writing Some orders into Text file under button control.It was writing under file system under my physical directory. suddenly i got error :

Could not find a part of the path 'D:\SavingTextfile\sampletext_44.txt'. 

I wrote in web.config file:

<Appsettings>

<add key="OrdersList" value="D:\\SavingTextfile\\sampletext.txt"/>

</Appsettings>

In Local system,i am storing like this:

D:\sampletext

My Code:

 protected void btnSubmit_Click(object sender, EventArgs e)

    {
         string Orderslist = System.Configuration.ConfigurationManager.AppSettings["OrdersList"].ToString();


                        string fileName = Orderslist;

                        string fileText = fileName + "_" +DateTime.Now.ToString();
                        fileText = fileText.Replace(".txt", "") + ".txt";
                        fileText = fileText.Trim();



                                //Check if file already exists. If yes, delete it. 
                                if (File.Exists(fileText))
                                {
                                    File.Delete(fileText);
                                }

                                // Create anew file 
                                using (StreamWriter streamWriter = new StreamWriter(fileText))
                                {
                                    streamWriter.WriteLine("order1");

                                  streamWriter.WriteLine("order2");

}

}

Thanks in Advance: