Hi,
I have found the solution by Disabling the Paging before INSERT and Enabling the Paging thereafter. Below code applies:
 
        protected void GridView1_AddNewRecord(object sender, EventArgs e)
        {
            string constr = ConfigurationManager.ConnectionStrings["LocalSqlServer"].ConnectionString;
            SqlConnection con = new SqlConnection(constr);
            SqlCommand cmd;
            string query1 = "INSERT INTO kart_Bestilling(SakBehandlingCode, KystverketRegionID, KystverketAvdelingID, BestillerReferanse, BestillerLeveringAdresse, BestillerPostKodeBy, BestillerNavn, BestillerStilling, BestillerEpost, BestillerTelefon, BestillingBeskrivelse, BestillingDato, BehandlingSakNummer, BehandlingBeskrivelse, BehandlingStatus)" +
                            " VALUES (@SakBehandlingCode, @KystverketRegionID, @KystverketAvdelingID, @BestillerReferanse, @BestillerLeveringAdresse, @BestillerPostKodeBy, @BestillerNavn, @BestillerStilling, @BestillerEpost, @BestillerTelefon, @BestillingBeskrivelse, @BestillingDato, @BehandlingSakNummer, @BehandlingBeskrivelse, @BehandlingStatus)";
            string query2 = "INSERT INTO kart_Order(kart_Bestilling.BestillingID, kart_Order.KartTypeID, kart_Order.KartNummerID, kart_Order.BestillingAntallKart1, kart_Order.KartPrisID) VALUES(@BestillingID, @KartTypeID, @KartNummerID, @BestillingAntallKart1, @KartPrisID)";
            if (GridView1.Rows.Count > 0)
            {
                GridView1.AllowPaging = false; // Disable the Parent GridView Paging
                try
                {
                    con.Open();
                    cmd = new SqlCommand(query1);
                    cmd.Connection = con;
                    cmd.Parameters.AddWithValue("@SakBehandlingCode", txtSakBehandlingCode.Text.Trim());
                    cmd.Parameters.AddWithValue("@KystverketRegionID", dropDownKystverketRegionNavn.SelectedValue);
                    cmd.Parameters.AddWithValue("@KystverketAvdelingID", dropDownKystverketAvdelingNavn.SelectedValue);
                    cmd.Parameters.AddWithValue("@BestillerReferanse", txtBestillerReferanse.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerLeveringAdresse", txtBestillerLeveringAdresse.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerPostKodeBy", txtBestillerPostKodeBy.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerNavn", txtBestillerNavn.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerStilling", txtBestillerStilling.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerEpost", txtBestillerEpost.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillerTelefon", txtBestillerTelefon.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillingBeskrivelse", txtBestillingBeskrivelse.Text.Trim());
                    cmd.Parameters.AddWithValue("@BestillingDato", txtBestillingDato.Text.Trim());
                    cmd.Parameters.AddWithValue("@BehandlingSakNummer", txtBehandlingSakNummer.Text.Trim());
                    cmd.Parameters.AddWithValue("@BehandlingBeskrivelse", txtBehandlingBeskrivelse.Text.Trim());
                    cmd.Parameters.AddWithValue("@BehandlingStatus", dropDownBehandlingStatus.SelectedValue);
                    cmd.ExecuteNonQuery();
                    GridView1_BindData();
                    GridView1_BindData2();
                }
                catch (Exception ee)
                {
                    lblMessage.Text = "--- Opps! Bestilling Annullert: Glemt Region/Avdeling?";
                }
                finally
                {
                    con.Close();
                }
                int rowIndex = 0;
                if (ViewState["CurrentTable"] != null)
                {
                    DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
                    if (dtCurrentTable.Rows.Count > 0)
                    {
                        for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
                        {
                            // 111111111111111111111111111111111111111111111111111111111111111111111111111111
                            DropDownList ddKartTypeName = (DropDownList)Gridview2.Rows[rowIndex].Cells[1].FindControl("dropDownKartTypeName");
                            DropDownList ddKartNummerName = (DropDownList)Gridview2.Rows[rowIndex].Cells[2].FindControl("dropDownKartNummerName");
                            TextBox tBestillingAntallKart1 = (TextBox)Gridview2.Rows[rowIndex].Cells[3].FindControl("txtBestillingAntallKart1");
                            DropDownList ddKartPrisTall = (DropDownList)Gridview2.Rows[rowIndex].Cells[3].FindControl("dropDownKartPrisTall");
                            // 111111111111111111111111111111111111111111111111111111111111111111111111111111
                            try
                            {
                                con.Open();
                                cmd = new SqlCommand(query2);
                                cmd.Connection = con;
                                // Last Row ID in the table
                                Int32 index = GridView1.Rows.Count - 1;
                                string bestillingId = GridView1.DataKeys[index].Values["BestillingID"].ToString();
                                cmd.Parameters.AddWithValue("@BestillingID", bestillingId);
                                cmd.Parameters.AddWithValue("@KartTypeID", ddKartTypeName.SelectedValue);
                                cmd.Parameters.AddWithValue("@KartNummerID", ddKartNummerName.SelectedValue);
                                cmd.Parameters.AddWithValue("@BestillingAntallKart1", tBestillingAntallKart1.Text.Trim());
                                cmd.Parameters.AddWithValue("@KartPrisID", ddKartPrisTall.SelectedValue);
                                cmd.ExecuteNonQuery();
                            }
                            catch (Exception ee)
                            {
                                // lblMessage.Text = "forget Region/Avdeling?";
                            }
                            finally
                            {
                                con.Close();
                            }
                            GridView1_BindData();
                            GridView1_BindData2();
                            rowIndex++;
                        }
                    }
                }
                GridView1_BindData();
                GridView1_BindData2();
            }
            QueryResult.Text = "Record Added successfully!";
            // Disable Submit Button
            btnAdd.Enabled = false;
            // Enable the Parent GridView paging
            GridView1.AllowPaging = true;
        }