I have nothing but respect for your knowledge and expertise, but regardless of the rest of the project is, I can't seem to find any code that can add a book, name it, copy a sheet into it, save it, and close it all inside a loop without errors. If I could just get this code I would happily work backwards. I can't seem to get this to happen even if I take everything else out of the macro. I stripped everything down to this simple loop in a separate book and it still errors in the exact same way. There is something fundamentally wrong that has nothing to do with the rest of my code or data. If you put this in a module, set the paths respectively and run it it fails (for me at least):

Sub TestLoopSample()Dim i As Integer
For i = 1 To 20
Application.DisplayAlerts = False
Dim NewBook         As Workbook
FPath = "Define"
FName = "Test" & i & ".xlsx"
Set NewBook = Workbooks.Add
NewBook.SaveAs Filename:=FPath & "\" & FName
ThisWorkbook.Sheets("CopyMe").Copy Before:=NewBook.Sheets(1)
NewBook.Close False
Application.DisplayAlerts = True
Next i
End Sub