Error Creating Chart

Hey guys,

I am trying to create a chart of data based on the user's selection of data. The code is below:

Private Sub CommandButton1_Click()
    Charts.Add
    ActiveChart.ChartType = xlXYScatterLines
    ActiveChart.SetSourceData Source:=Sheets("PFIR").range("A1:I3"), PlotBy:= _
        xlRows
    ActiveChart.SeriesCollection.NewSeries
    ActiveChart.SeriesCollection.NewSeries
    ActiveChart.SeriesCollection.NewSeries
    ActiveChart.SeriesCollection.NewSeries
    ActiveChart.SeriesCollection(1).XValues = Worksheets("Data").range(Worksheets("Data").Cells(6, 2), Worksheets("Data").Cells(lastrow, 2))
    ActiveChart.SeriesCollection(1).Values = Worksheets(reactorone).range(lineonerow, lineonecolumn)
    ActiveChart.SeriesCollection(2).XValues = xtime
    ActiveChart.SeriesCollection(2).Values = linetwo
    ActiveChart.SeriesCollection(3).XValues = xtime
    ActiveChart.SeriesCollection(3).Values = linethree
    ActiveChart.SeriesCollection(4).XValues = xtime
    ActiveChart.SeriesCollection(4).Values = linefour
    ActiveChart.Location Where:=xlLocationAsNewSheet
    With ActiveChart
        .HasTitle = False
        .Axes(xlCategory, xlPrimary).HasTitle = False
        .Axes(xlValue, xlPrimary).HasTitle = False
    End With
End Sub

The line that spits back the error is:

ActiveChart.SeriesCollection(1).XValues = Worksheets("Data").range(Worksheets("Data").Cells(6, 2), Worksheets("Data").Cells(lastrow, 2))

It gives me an error saying something about object or application undefined. I don't understand why this would possibly kick back an error, I have specifically referenced each cell and lastrow is an integer value.

Does anyone have any ideas?

~Jason

Hi:
I use something like this:

ActiveChart.SeriesCollection(1).XValues = "=Data!R" & InitialRow &
"C" & Col & ":R" & EndRow & "C" & Col

Hope this help