Macro - Runtime Error

I have a line chart which I created which shows data on one axis. I created a macro which when clicked by the user creates a secondary axis and shows this data on the chart as well. I also have another macro which resets the chart back to one axis and only displays data along that single axis.

It all works fine except if you click the macro button twice (either for it to show the secondary axis and data or if you click the reset button twice). I get the following error message:

Runtime Error '1004':
Unable to set the AxisGroup property of the Series class

Here's the VBA code:

ActiveSheet.ChartObjects("Chart 160").Activate
ActiveChart.Axes(xlValue).MajorGridlines.Select
ActiveChart.PlotArea.Select
ActiveChart.SetSourceData Source:=Sheets("USD Pivot").Range("A52:B58,D52:D58" _
), PlotBy:=xlColumns
ActiveChart.SeriesCollection(2).Select
ActiveChart.SeriesCollection(2).AxisGroup = 2
ActiveChart.Axes(xlValue, xlSecondary).Select
Selection.TickLabels.AutoScaleFont = True
With Selection.TickLabels.Font
.Name = "Futura Medium"
.FontStyle = "Regular"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
.Background = xlAutomatic
End With
Selection.TickLabels.AutoScaleFont = True
With Selection.TickLabels.Font
.Name = "Futura Medium"
.FontStyle = "Regular"
.Size = 10
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
.Background = xlAutomatic
End With
ActiveChart.Axes(xlValue).MajorGridlines.Select
ActiveChart.ChartArea.Select
ActiveChart.PlotArea.Select
With ActiveChart
.Axes(xlValue, xlSecondary).HasTitle = True
.Axes(xlValue, xlSecondary).AxisTitle.Characters.Text = "AGO Vol (Litres)"
End With
ActiveChart.ChartArea.Select
ActiveChart.Axes(xlValue, xlSecondary).AxisTitle.Select
Selection.AutoScaleFont = True
With Selection.Font
.Name = "Futura Medium"
.FontStyle = "Regular"
.Size = 10
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
.Background = xlAutomatic
End With
ActiveWindow.Visible = False
Windows("CRT Rebate Savings Tracker September 2008.xls").Activate
Range("J1").Select
ActiveWindow.SmallScroll Down:=-6
End Sub