Global Address book not updating

Microsoft Exchange 2003
Outlook 2007

Check this out: http://support.microsoft.com/default.aspx?scid=kb;en-us;288807

That link will help you to Troubleshoot the Recipient Update Service on Exchange 2003.

Things I did before it started working again:

1. Rebuilt the Default Offline Address List
2. Rebuilt the Recipient Update Service
3. Restarted the System Attendant Service
4. Opened Outlook, clicked on Tools–>Send/Receive–>Download Address Book.
   Uncheck the Download Changes…box and make sure it is set to Full Details and click OK.
5. then check the Address Book and see if it is updating