Why do I keep getting this error

Run-time error '1004'
Unable to set the Width property of the Windows clas

In my ThisWorkbook object I have the following code

Private Sub Workbook_Open(
With ActiveWindo
.Width = 27
.Height = 27
End Wit
End Su

This only errors out when I open Excel with the file. If Excel is already open, no error

The worksheet is not protected

Thanks.