I am running into an issue when i try to execute this macro in excel (the bold part is where the error happens):

Sub ZoomIn()

Dim LeftHorizScale As Long

Dim RightHorizScale As Long

Dim TopVertScale As Long

Dim BottomVertScale As Long

Dim i As Long

Dim NumDataPoints As Long

Dim InitialPoint As Integer

Dim LastPoint As Integer

With Selection

.MarkerSize = 2

End With

Sheets("cal & data").Select

NumberDataPoints = Range("B65").Value

Sheets("Sigma1vData").Select

InitialPoint = -1

LastPoint = -2

For i = 1 To NumberDataPoints - 1

** If ActiveChart.SeriesCollection(1).Points(i).MarkerSize = 2 Then**

If InitialPoint = -1 Then

InitialPoint = i

Else

LastPoint = i

End If

End If

Next i

P.S. this error only happens when i have over 14000 rows of data to deal with so i know it has something to do with that but i am just not sure where to proceed. I tried altering all the parameters from integer to long but no success. Any help would be greatly appreciated. Thank you