Excel宏在PC上运行但不在Mac上运行，为什么？我如何解决它？

Question

我正在构建一个Excel宏差异工具，它显示两个工作表之间的差异。我在PC上构建了这个工具，它可以工作，但是当我在Mac上运行它时，我得到一个运行时错误（＆＃39; 9＆＃39;）。当我调试时，错误突出显示设置的工作表行。这是我的代码：

Dim filepath As String
Dim num As String
Dim workbookname As String
Dim worksheet As Worksheet

filepath = txtOriginalWorkbook.Text 'assigning a variable to the file location 
num = txtOriginalSheetNumber.Text 'this is always numeric
workbookname = getFileName(filepath) 'gets the file name from the file path 
Set worksheet = Workbooks(workbookname).Worksheets(CInt(num)) 

最后一行突出显示为错误