运行时错误'91'对象变量或未设置块变量的操作较早

Question

我的代码一直运行到今天。我不确定为什么在设置块变量时出现错误。错误发生在我的vlookup中。

Sub oversub()
Application.ScreenUpdating = False
    'Latest File Code
    Dim MyPath As String
    Dim MyFile As String
    Dim LatestFile As String
    Dim LatestDate As Date
    Dim LMD As Date

    MyPath = "C:\Users\TAmon1\Desktop\....."
    If Right(MyPath, 1) <> "\" Then MyPath = MyPath & "\"
    MyFile = Dir(MyPath & "*.csv", vbNormal)
    If Len(MyFile) = 0 Then
        MsgBox "No files were found...", vbExclamation
        Exit Sub
    End If
    Do While Len(MyFile) > 0
        LMD = FileDateTime(MyPath & MyFile)
        If LMD > LatestDate Then
            LatestFile = MyFile
            LatestDate = LMD
        End If
        MyFile = Dir
    Loop

Workbooks.Open MyPath & LatestFile
'Variables for Vlookup

Dim wbcsv As Workbook, wbplanning As Workbook
Set wbplanning = Workbooks("Planning_tool.xlsm")
Set wbcsv = Workbooks.Open(MyPath & LatestFile)
Dim wb As Workbook
Set wb = Workbooks.Open(MyPath & LatestFile)

Windows("Planning_tool.xlsm").Activate

#The error occurs here 
wbplanning.Sheets(1).Range("N2").FormulaR1C1 = _
"=VLOOKUP(C[-13],'" & wbcsv.Name & "'!C1:C11,11,FALSE)"
Range("N2").Select
Selection.AutoFill Destination:=Range("N2:N2000")

wbplanning.Sheets(1).Range("o2").FormulaR1C1 = _
"=VLOOKUP(C[-14],'" & wbcsv.Name & "'!C1:C11,5,FALSE)"
Range("o2").Select
Selection.AutoFill Destination:=Range("o2:o2000")
Columns("N:O").Select
Application.CutCopyMode = False
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False

wb.Close savechanges:=False



End Sub

我的vlookup对象变量未设置错误。该代码较早就可以正常工作，所以我不确定从昨天开始有什么变化。