Increase stocks to other table

Question

i got error when using this code

My Tables are

===============================

PRODUCT TR_RECEIVE_PRODUCT

>ID_PRODUCT >ID_RECEIVE_PRODUCT

>NAME >ID_PRODUCT

>CURRENT_STOCK >DATE_IN

>STOCK_IN

====================================

=============================================================================

Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click

        Dim cmd As New SqlCommand

        Dim connectionString As String = "Data Source=.|dbDIR|;Integrated Security=True;Connect Timeout=30;User Instance=True"

        con = New SqlConnection(connectionString)

        If Not con.State = ConnectionState.Open Then

            con.Open()

        End If

        cmd.Connection = con

        Try

            cmd.CommandText = "INSERT INTO TR_RECEIVE_PRODUCT(ID_RECEIVE_PRODUCT, ID_PRODUCT, DATE_IN, STOCK_IN) VALUES ('" & Me.txtID_RECEIVE_PRODUCT.Text & "', '" & Me.cmbID_PRODUCT.SelectedValue & "', '" & _

                                Me.DateTimePicker1.Value.ToString("yyyy-MM-dd") & "', '" & Me.txtSTOCK_IN.Text & "')"

            cmd.ExecuteNonQuery()

        Catch

            MsgBox("ERROR", MsgBoxStyle.Critical, "Error")

        End Try

        cmd.CommandText = "SELECT * FROM PRODUCT WHERE ID_PRODUCT='" & dgvTB.CurrentRow.Cells(1).Value & "'" 

        cmd = New SqlCommand(cmd.CommandText, con)

        cmd.ExecuteReader()

        If cmd.ExecuteReader.Read = True Then

            current_stock = Convert.ToInt32(cmd.ExecuteReader(5).ToString)

            stock_in = Convert.ToInt32(dgvTB.CurrentRow.Cells(3).Value)

            qty = stock_in + current_stock

            con.Close()

            con.Open()

            cmd.CommandText = "UPDATE PRODUCT SET CURRENT_STOCK='" & qty & "' WHERE ID_PRODUCT='" & dgvTB.CurrentRow.Cells(1).Value & "'"

            cmd = New SqlCommand(cmd.CommandText, con)

            cmd.ExecuteNonQuery()

            MsgBox("stock has been updated", MsgBoxStyle.Information)

            con.Close()

        Else

            MsgBox("Error", MsgBoxStyle.OkOnly)

        End If

        Me.GetData()

        Clear()

        con.Close()

===============================

some error include these statement:

cmd.CommandText = "SELECT * FROM PRODUCT WHERE ID_PRODUCT='" & dgvTB.CurrentRow.Cells(1).Value & "'"

 If cmd.ExecuteReader.Read = True Then

well, the record is still recorded, but the stocks on PRODUCT table won't increased :((