ماذا يعني هذا الخطأ اثناء الحفظ

كود :

Try

            Dim Sql = "Select * From ReceiptOfltems Where VoucherCode=N'" & (VoucherCode.Text) & "'"

            Dim Adp As New SqlClient.SqlDataAdapter(Sql, SQLConn)

            Dim DS As New DataSet

            Adp.Fill(DS)

            Dim DT = DS.Tables(0)

            If DT.Rows.Count > 0 Then

                '******************************************************************************************************************************

                VoucherCode.Text = Format(GET_LAST_RECORD("ReceiptOfltems", "Voucherid") + 1, "ROF000000")

                SupplierlnVoiceCode.Text = GET_LAST_RECORD("ReceiptOfltems", "Voucherid") + 1

                '******************************************************************************************************************************

            Else

                Dim DR = DT.NewRow

                DR!VoucherCode = VoucherCode.Text

                DR!VoucherDate = VoucherDate.Value

                DR!SupplierCode = SupplierCode.Text

                DR!SupplierName = SupplierName.Text

                DR!SupplierlnVoiceCode = SupplierlnVoiceCode.Text

                DR!SupplierlnvoiceDate = SupplierlnvoiceDate.Value

                DR!SupplierInVoiceType = SupplierInVoiceType.Text

                DR!SalesTAX = Val(SalesTAX.Text)

                DR!Notes = Notes.Text

                DR!TotalQty = TotalQty.Text

                DR!TotalDiscount = Val(TotalDiscount.Text)

                DR!TotalVoucher = Val(TotalVoucher.Text)

                DR!TotalArabic = TotalArabic.Text

                DR!Status = True

                DT.Rows.Add(DR)

                Dim Cmd As New SqlClient.SqlCommandBuilder(Adp)

                Adp.Update(DT)

            End If



            BtnNew_Click(Nothing, Nothing)

            MsgBox(" تم حفظ سند التوريد فى قاعدة البيانات بنجاح", MsgBoxStyle.Information, "رسالة تأكيد")



        Catch ex As Exception

            MessageBox.Show(ex.Message, "فشل في الحفظ  ", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1, MessageBoxOptions.DefaultDesktopOnly)



        End Try

كود :

Sub Showrecord(Vcode As String)



        DataGridView1.Rows.Clear()

        Dim Sql = "Select * From ReceiptOfltems Where VoucherCode=N'" & (Vcode) & "'"

                Dim Adp As New SqlClient.SqlDataAdapter(Sql, SQLConn)

        Dim DS As New DataSet

        Adp.Fill(DS)

        Dim DT = DS.Tables(0)

        If DT.Rows.Count = 0 Then

            MsgBox("عزيزى عفواً لم يتم العثور على السند يرجى التأكد من الرقم", MsgBoxStyle.Exclamation, "تنبيه")

        Else

            Dim DR = DT.Rows(0)



            VoucherCode.Text = CType((DR!VoucherCode), String)

            VoucherDate.Text = CType((DR!VoucherDate), String)

            SalesTAX.Text = CType((DR!SalesTAX), String)



            Notes.Text = CType((DR!Notes), String)



            SupplierCode.Text = CType((DR!SupplierCode), String)

            SupplierName.Text = CType((DR!SupplierName), String)

            SupplierInVoiceType.Text = CType((DR!SupplierInVoiceType), String)

            SupplierlnVoiceCode.Text = CType((DR!SupplierlnVoiceCode), String)

            SupplierlnvoiceDate.Text = CType((DR!SupplierlnvoiceDate), String)



            TotalQty.Text = CType((DR!TotalQty), String)



            TotalDiscount.Text = CType((DR!TotalDiscount), String)

            TotalVoucher.Text = CType((DR!TotalVoucher), String)

            TotalArabic.Text = CType((DR!TotalArabic), String)

            DR!Status = True



        End If

        Adp.Dispose()

        DS.Dispose()

        DT.Dispose()



    End Sub