‘Ya hay un lector de datos abierto asociado con esta conexión que debe cerrarse primero.’

Buenas noches chicos, están escribiendo este código pero me dice que tengo un ExecuteReader abierto.
Me puedes dar una mano
Gracias

Lo que he probado:

        Dim namecontr As String
        Dim rdr3 As Object

        Dim cmd3 As New MySqlCommand("Select s01_name_contr  from s01_tpcontratti where id=" & rdr.Item(2), cnnmysql)
        rdr3 = cmd3.ExecuteReader
        rdr3 = cmd3.ToString   ' 03/12 ore 17:25 capire perche non mi funziona si blocca 29/12 non ancora sbloccato
        'cmd3.Dispose()

        '  rdr3.Read()



        If rdr3.HasRows = True Then
            namecontr = rdr3.Item(0).ToString
        End If

        Dim data As Date = CDate(rdr.Item(3).ToString)
        grid_contratto.Rows.Add(rdr(0).ToString, rdr(2).ToString, namecontr, "stocazzo", data.ToShortDateString)
        '   rdr3.close()
    Loop
    rdr.Close()

    'cnnmysql.Clone()

End Sub

EDITAR: código OP de la “Solución 1” y Solución eliminada

Private Sub carica_grigliacontratti(id As String)
    '  Call connetti_mysql()
    ' cnnmysql.Open()

    If CInt("0" & id) = 0 Then Exit Sub
    Dim sql As String
    Dim rdr As Object
    ' Dim rdr2 As Object
    '  grspecialisti.Rows.Clear()


    sql = "Select * from a01_contratti where a01_cliente=" & id


    Dim cmd1 As New MySqlCommand(sql, cnnmysql)

    rdr = cmd1.ExecuteReader()
    cmd1.Dispose()


    If rdr.HasRows = False Then
        rdr.Close()

        Exit Sub
    End If
    sistema_grcerca()

    '    Dim perc As Long = 0
    '        Dim volte As Integer = 0w
    cnnmysql.Clone()
    grid_contratto.Rows.Clear()

    Do While rdr.Read

        Dim namecontr As String
        Dim rdr3 As Object

        Dim cmd3 As New MySqlCommand("Select s01_name_contr  from s01_tpcontratti where id=" & rdr.Item(2), cnnmysql)
        rdr3 = cmd3.ExecuteReader
        rdr3 = cmd3.ToString   ' 03/12 ore 17:25 capire perche non mi funziona si blocca 29/12 non ancora sbloccato
        'cmd3.Dispose()

        '  rdr3.Read()



        If rdr3.HasRows = True Then
            namecontr = rdr3.Item(0).ToString
        End If

        Dim data As Date = CDate(rdr.Item(3).ToString)
        grid_contratto.Rows.Add(rdr(0).ToString, rdr(2).ToString, namecontr, "stocazzo", data.ToShortDateString)
        '   rdr3.close()
    Loop
    rdr.Close()

    'cnnmysql.Clone()

End Sub