creating a sparkline using VBA

It appears to be working.

Private Sub SparklineTest_Click()
Dim LINE As SparklineGroup
Dim ws As Worksheet
Set ws = Sheets("Sheet1")

Dim lastrow As Integer
lastrow = Cells(Rows.Count, 1).End(xlUp).Row
Set LINE = ws.Range("F2").SparklineGroups.Add(Type:=xlSparkLine, SourceData:="Sheet1!A2:A" & lastrow)

End Sub

When you said initially, the range doesn't make sense, which part of the code were your referring to?