If autodiscovery is not configured for your domain name you will see a regular stream of error messages appearing in the Sync Issues folder in Outlook 2007.

They look like this:

12:18:17 Synchronizer Version 12.0.4518
12:18:17 Synchronizing Mailbox
12:18:17 Done
12:18:27 Microsoft Exchange offline address book
12:18:27 Not downloading Offline address book files. A server (URL) could not be located.
12:18:27 0X8004010F

To fix this you'll need to add an autodiscovery record to your DNS. You can find out more about this here.