Cant back up a db error version is not supported

Backup failed for Server '\\.\pipe\6754F9F4-3FC4-42\tsql\query'. 
 this version is not supported

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using Microsoft.SqlServer.Management;
using Microsoft.SqlServer.Management.Smo;
using System.Data;
using System.Data.SqlClient;
using System.Collections.Specialized;
using System.IO;
using Microsoft.SqlServer.Management.Common;



namespace ChequeText
{
    class BackupRestore : DBConnection
    {


        /// <summary>
        /// Backup the database
        /// </summary>
        internal void TakeBackUp()
        {
            //if(MessageConfirmation.MessageShowYesNo("Do you want to take back up?"))
            // if (MessageBox.Show("Do you want to take back up?", "My Soft", 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)
                    {
                       msgBox.Commen(ex.ToString() );
                       // MessageBox.Show("Backup failed for Server .  (Microsoft.SqlServer.Smo)", "Bank Software", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    finally
                    {
                        sqlcon.Close();
                    }
                }
            }
        }