Android Question Unparseable Date

Sub lblSelFecha_Click
    Dim Fecha As DateDialog
    Dim ret As String
    
    Fecha.DateTicks = DateTime.Now
    ret = Fecha.Show("Seleccione Fecha Desde", "Ventas", "OK", "Salir", "", Null)
    If ret = DialogResponse.CANCEL Then Return
    DateTime.TimeFormat="dd-MM-yyyy"
    txtFecha.Text = DateTime.time(Fecha.DateTicks)
    DateTime.TimeFormat="dd-MM-yyyy"
    'AuxDesde = DateTime.time(Fecha.DateTicks)
    'LongDesde = DateTime.DateParse(AuxDesde)
    LongDesde = DateTime.time(Fecha.DateTicks)

    'CargarTabla
End Sub

Sub CargarTabla
    Dim Tbid As Int
    Dim TbFecha As String
    Dim TbHora As String
    Dim TbValor As Int
    Dim AuxAcum As Int

    Table1.ClearAll
    CurTabla = Main.DbMain.ExecQuery("Select * from boletas Where Fecha >= '" & txtFecha.Text & "' and Fecha <= '" & txtHasta.Text & "';")
    AuxAcum = 0
    If CurTabla.RowCount > 0 Then
        For i = 0 To CurTabla.RowCount - 1
            CurTabla.Position = i
            Tbid = CurTabla.GetInt("id")
            TbFecha = CurTabla.GetString("Fecha")
            TbHora = CurTabla.GetString("Hora")
            TbValor = CurTabla.GetInt("Valor")
            AuxAcum = AuxAcum + TbValor
            Table1.AddRow(Array As String(Tbid,TbFecha,TbHora,TbValor))
        Next
        Table1.AddRow(Array As String("","","",""))
        Table1.AddRow(Array As String("","","Boletas:",CurTabla.RowCount))
        Table1.AddRow(Array As String("","","TOTAL:",AuxAcum))
    Else
        Msgbox("No Hay Ventas para este Periodo","Detalle Ventas")
    End If
End Sub

Sub lblSelHasta_Click
    Dim Fecha As DateDialog
    Dim ret As String
    
    
    Fecha.DateTicks = DateTime.Now
    ret = Fecha.Show("Seleccione Fecha Hasta", "Boleta", "OK", "Salir", "", Null)
    If ret = DialogResponse.CANCEL Then Return
    DateTime.TimeFormat="dd-MM-yyyy"
    txtHasta.Text = DateTime.time(Fecha.DateTicks)
    DateTime.TimeFormat="dd-MM-yyyy"
    'AuxHasta = DateTime.time(Fecha.DateTicks)
    'LongHasta = DateTime.DateParse(AuxHasta)
    LongHasta = DateTime.time(Fecha.DateTicks)
    
    If LongDesde <= LongHasta Then
        CargarTabla
    Else
        Msgbox("Fecha Desde debe ser Menor fecha Hasta","Boleta")
    End If
End Sub