If you are using older versions of Excel you will probably get some error messages when opening a workbook or running a macro. This is caused by the fact that I'm usually using the latest edition of Excel when I create most of the examples, and I haven't got the opportunity to test all examples in the older versions of Excel. Because of this the workbooks often refers to libraries that doesn't exist if you have an older version of Excel. To remove the error messages you can do this:

1. Select a module sheet in the workbook that causes the error message.
2. Select the menu Tools, References.
3. Remove the tick mark from the missing object libraries, add a reference to a similar (older) object library.
   Click the OK-button.
4. Save, close and reopen the workbook, this time the error message should be gone.