data base back up failed in sql 2008

internal void TakeBackUp()
        {
            //if(MessageConfirmation.MessageShowYesNo("Do you want to take back up?"))
            // if (MessageBox.Show("Do you want to take back up?", "A2zSchool", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            if (MessageBox.Show("Do you want to take back up?", "Bank", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            {
                if (sqlcon.State == ConnectionState.Closed)
                {
                    sqlcon.Open();
                }
                string DBName = sqlcon.Database; ;
                string[] arr = DBName.Split('\\');
                DBName = arr[arr.Length - 1].Replace(".MDF", "");
                string DBFolder = arr[arr.Length - 2];
                ServerConnection srvConn = new ServerConnection(sqlcon);
                SaveFileDialog saveBackupDialog = new SaveFileDialog();
                Server srvSql = new Server(srvConn);
                string path = Application.StartupPath + @"\Data\DBBankCheque.mdf";
                srvSql = new Server(srvConn);
                DateTime BackupDate = DateTime.Now;
                string BakDt = BackupDate.ToString("ddMMyyyhhmmss");
                string FName = "Bank---" + DBFolder + "-" + BakDt + ".bak";
                saveBackupDialog.FileName = FName;
                if (saveBackupDialog.ShowDialog() == DialogResult.OK)
                {
                    Backup bkpDatabase = new Backup();
                    bkpDatabase.Action = BackupActionType.Database;
                    bkpDatabase.Database = path;
                    BackupDeviceItem bkpDevice = new BackupDeviceItem(saveBackupDialog.FileName, DeviceType.File);
                    bkpDatabase.Devices.Add(bkpDevice);
                    try
                    {
                        bkpDatabase.SqlBackup(srvSql);

                       MessageBox.Show("The backup of database  completed successfully ", "Bank", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        //   MessageBoxes.messageBoxShow("The backup of database  completed successfully");

                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("Backup failed for Server .  (Microsoft.SqlServer.Smo)", "Bank Software", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    finally
                    {
                        sqlcon.Close();
                    }
                }
            }
        }