Vba - insert popup calendar

HI ALL
trying to insert pop up calendar found this vba works ok in new blank sheet but if I try to enter in to attached sheet come up error
I am trying to get pop up calendar in cells A8 to A150 & G8 to G150 with out success got excel calendar on ok but found vba on here but cant get it to work any help please need to be entered to every month

VBA CODE
Private Sub Calendar1_Click()
    ActiveCell.Value = CDbl(Calendar1.Value)
    ActiveCell.NumberFormat = "dd/mm/yyyy"
    ActiveCell.Select
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    If Target.Cells.Count > 1 Then Exit Sub
    If Not Application.Intersect(Range("A8:A150"), Target) Is Nothing Then
        Calendar1.Left = Target.Left + Target.Width - Calendar1.Width
        Calendar1.Top = Target.Top + Target.Height
        Calendar1.Visible = True
        ' select Today's date in the Calendar
        Calendar1.Value = Date
    ElseIf Calendar1.Visible Then Calendar1.Visible = False
    End If
End Sub