Error - Object variable or With block variable not set

I have two macros which work fine separately. I have combined them (see the line ' insert 12 columns and label) - now get an error.
Object variable or With block variable not set
I have no idea what this means. The macro executes all the way through to this section, then the error pops up:

Find the phrase "This Year"
    Cells.Find(What:="This Year", After:=ActiveCell, LookIn:=xlFormulas, _
        LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
        MatchCase:=False, SearchFormat:=False).Activate
        
'   Capture column where this resides
    myColumn = ActiveCell.Column

Here's the full code:

Sub border_highlight_insert()
‘  Change heavy border to new column, change tint – keyed to year A6

With ActiveSheet

Dim i As Integer

    i = [A6] - 2010

    .Range(.Cells(9, i), .Cells(50, 4)).Borders.LineStyle = Excel.XlLineStyle.xlLineStyleNone
 
     .Range(.Cells(9, i), .Cells(50, 4)).Select
    With Selection.Interior
        .Pattern = xlNone
        .TintAndShade = 0
        .PatternTintAndShade = 0
    End With
    Range("E9:E50").Select
    Range("E50").Activate
    With Selection.Interior
        .Pattern = xlSolid
        .PatternColorIndex = xlAutomatic
        .Color = 13434828
        .TintAndShade = 0
        .PatternTintAndShade = 0
   End With
    With Selection.Borders(xlEdgeLeft)
        .LineStyle = xlContinuous
        .Weight = xlMedium
    End With
    With Selection.Borders(xlEdgeTop)
        .LineStyle = xlContinuous
        .Weight = xlMedium
    End With
    With Selection.Borders(xlEdgeBottom)
        .LineStyle = xlContinuous
        .Weight = xlMedium
    End With
    With Selection.Borders(xlEdgeRight)
        .LineStyle = xlContinuous
        .Weight = xlMedium
    End With

‘   insert 12 columns and label

Sheets(“Expense Tracking”).Select
Range(A1).select

    Dim myColumn As Long
    Dim myCol As Long

'   Find the phrase "This Year"
    Cells.Find(What:="This Year", After:=ActiveCell, LookIn:=xlFormulas, _
        LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
        MatchCase:=False, SearchFormat:=False).Activate
        
'   Capture column where this resides
    myColumn = ActiveCell.Column
    
'   Insert 12 blank columns to the left of this column
    Range(Cells(8, myColumn), Cells(8, myColumn + 11)).EntireColumn.Insert , CopyOrigin:=xlFormatFromLeftOrAbove
    
'   Populate row 8 with month numbers
    For myCol = 1 To 12
        Cells(8, myColumn + myCol - 1) = Format(DateSerial(2000, myCol, 1), "mmm")
    Next myCol

End With
End Sub

Any help would be much appreciated!!
Thanks,
Mike