Unable to define Object in Excel - excel

Question

In the below code I declared r as a variant and did r = twb.Worksheets("Log").Range("b2") but I am getting a Error 424 for missing object. I thought by declaring it and defining it would resolve the issue. The code breaks in the "Select Values from cells" section of the code.
The function used to handle special characters in cells is:
Function ValidFileName(ByVal FileName As String) As String
Dim myarray() As Variant
Dim x
'check for illegal characters
myarray = Array("[", "]", "\\", "/", "*", "\", "?", "<>", "<", ">", ":", "|", "&")
For x = LBound(myarray) To UBound(myarray)
FileName = Replace(FileName, myarray(x), "", 1)
Next x
ValidFileName = FileName
End Function
And the code that I am trying to resolve is:
Option Explicit
Sub RenameExcelInDir()
Dim MyPath As String
Dim MyFile As String
Dim MyExt As String
Dim MyNewName As String
Dim wb As Workbook
Dim twb As Workbook
Dim wks As Worksheet
Dim r As Variant '<---- Causing error
Dim getDate As Date
'Opens File Dialog Window to choose dir to search in
With Application.FileDialog(msoFileDialogFolderPicker)
.Show
MyPath = .SelectedItems(1)
End With
Set twb = ThisWorkbook
r = twb.Worksheets("Log").Range("B2")
MyFile = Dir(MyPath & "\*.*")
Do While Len(MyFile) > 0
MyExt = Split(MyFile, ".")(UBound(Split(MyFile, ".")))
Set wb = Workbooks.Open(MyPath & "\" & MyFile, UpdateLinks:=0)
'Loops through the worksheet collection
For Each wks In wb.Worksheets
Select Case wks.Name
Case "ISU Form"
MyNewName = ValidFileName(FileName:=wb.Sheets("ISU FORM").Range("C23").Value & "." & MyExt)
Case "GLOBAL ISU"
MyNewName = ValidFileName(FileName:=wb.Sheets("GLOBAL ISU").Range("M26").Value & "." & MyExt)
End Select
Next wks
wb.Close
'Select Values from cells
r.Value = MyFile
r.Offset(, 1).Value = MyNewName
Set r = r.Offset(1)
Name MyPath & "\" & MyFile As MyPath & "\" & MyNewName
MyFile = Dir
Loop
End Sub
Can I not use r as Variant? Does it have to be something else?