Error 91 VBA

Can someone please tell me what I'm doing wrong..

Private Sub UserForm_Initialize()
'2 of 3
     Dim properPullValue
     Dim numberOfTickers As Integer
     
     numberOfTickers = Worksheets("BasketCase").Range("C2").Value
    
    If numberOfTickers = 1 Then
    properPullValue = "BasketCase!$A$2"
    ElseIf numberOfTickers = 2 Then
    properPullValue = "BasketCase!$A$2:$A$3"
    Else
    properPullValue = "BasketCase!$A$2:$A$4"
    End If
    

    refTickers.Value = properPullValue
    boxStartDate.Value = Worksheets("BasketCase").Range("C5").Value
    boxEndDate.Value = Worksheets("BasketCase").Range("C7").Value
    With cboFrequency
        .AddItem "d"
        .AddItem "m"
        .AddItem "y"
        .Value = "d"

    End With ' cboFrequency
    refOutputRange.Value = "RawDataSheet!$A$1"
    cbDate = True
    cbOpen = True
    cbHigh = True
    cbLow = True
    cbClose = True
    cbVolume = True
    cbAdjClose = True
    labelErr.Caption = ""
    Call buttonDownload_Click
End Sub