Thank you for posting your question about how to get Outlook folders. This topic is covered in the Access 2007 VBA Programmer's Reference book, in Chapter 16. However, you do not use DAO to do this, instead you actually use the Outlook Object Model in this case.
Specifically, pages 538-540 of the Access 2007 VBA Programmer's Reference cover how to create a mail item, which includes how to get the Inbox mail folder for Outlook. Although this example is a general example about how to get the Inbox folder to send a new mail via Outlook from an Access database application, it should provide you with a good starting point and reference for the parts of the Outlook Object Model you need to use to get Outlook folders.
Anyway, I hope this helps, but if you have any more questions about this, please feel free to let me know!
Geoffrey L. Griffith
Co-author of the Access 2007 Programmer's Reference