What kind of module is the code in in the Personal.xlsm file? A Module, or a Sheet?

You should make Range references explicit. Without qualification it will default to the sheet which owns the code module. If it's not a sheet module but a Module module, then it should default to the active sheet. For example, you may need to change

Range("A1").Select
to 

ActiveSheet.Range("A1").Select
It may be worth your while to stop the code on that line in debug mode and see what the code thinks the active sheet/active workbook is.