Save file to location with the SaveFileDialog but the file allready exists!

Hi,

What can I do to save a file to a certain location with the SaveFileDialog but the same file allready exists! I get an message to override it. And I click Yes. But then I get an error:
   
System.IO.IOExeption: the file c:\Users\Peter\Desktop\DBRoot.bak already exists.

        private void bbBackup_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            string pathDB = Application.StartupPath + "\\DBRoot.mdb";
            glucsTA.Update(glucsDS);
            glucsDS.AcceptChanges();
            suppTA.Update(suppDS);
            suppDS.AcceptChanges();
            favorTA.Update(favorDS);
            favorDS.AcceptChanges();
            calenTA.Update(calenDS);
            calenDS.AcceptChanges();
            SaveFileDialog saveFileDlg = new SaveFileDialog();
            saveFileDlg.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            saveFileDlg.Filter = "Backup File (*.bak)|*.bak";
            saveFileDlg.FileName = "DBRoot.bak";
            try
            {
                if (saveFileDlg.ShowDialog() == DialogResult.OK)
                {
                    System.IO.File.Copy(pathDB, saveFileDlg.FileName);
                }
            }
            catch (Exception ex)
            {
                XtraMessageBox.Show(ex.ToString());
            }
        }

Select allOpen in new window

Greetings, Peter Kiers