Create folder (directory) and upload files using C# in ASP.Net

Hi All,

i have a few douts about the below file directory concept,

for creating file directory.

how can i create folder using file directory .

the code i have done but am getting the error,

please have a look my code below and let me know where i have done a mistake.

i want to create folder like below,

mch\\popages\\Terms\\clientname\\
--->clientname folder which is come from my class file
please refer my code below

code is :

protected void btnUpload_Click1(object sender, EventArgs e)
        {
            try
            {


                //if (ASBsupplier.Text == "")
                //{
                //    lblMessage.Text = "Select Supplier";
                //    return;
                //}

                if (FileUpload1.PostedFile.ContentLength == 0)
                    throw new ApplicationException("Select valid file");

                if (!Directory.Exists(Server.MapPath("..") + "\\mch\\popages\\Terms\\ClientName\\"))
                {
             


                    client = Helper.GetParentFolderName().ToString();
                    Directory.CreateDirectory(Server.MapPath("..") + "\\mch\\popages\\Terms\\" + client + "");

                   
                }

                FileName = FileUpload1.FileName;
                d_SelectedFileSize = FileUpload1.PostedFile.ContentLength / 1024;

                if (d_SelectedFileSize > 25)
                {
                    lblMessage.Text = "File size exceeds maximum limit 25 kb";
                    return;
                }


                if ("." + rbtnFormat.SelectedValue == Path.GetExtension(FileName))
                {
                    client = Helper.GetParentFolderName().ToString();
            
                    FilePath = Server.MapPath("..") + "\\mch\\popages\\Terms\\"+client+"\\" + ASBsupplier.Text + Path.GetExtension(FileName) + "";

                    if (System.IO.File.Exists(FilePath))
                    {
                        try
                        {
                            System.IO.File.Delete(FilePath);
                        }
                        catch (System.IO.IOException er)
                        {
                            throw er;
                        }
                    }

                    if (!File.Exists(FilePath))
                    {
                        FileUpload1.PostedFile.SaveAs(FilePath);
                        lblMessage.Text = "File saved successfully";
                    }
                }
                else
                {
                    throw new ApplicationException("Uploaded file format not matched with selected file format");
                }


            }
            catch (Exception ex)
            {
                lblMessage.Text = ex.Message;
            }
        }

thanks in advance..