Wrd hangs when inserting .jpg files

After upgrading W2K3 server to Domain controller, inserting .jpg files from server shared folder into Office 2003 app causes app to hang. Network has WinXP SP2 clients and 2 MAC clients – 1 OS9 and 1 OS10. Have had to Disable Digital Signing from Domain Security Policy to allow MAC to access server. XP SP2 Firewall disabled makes no difference. Can access files in share frm client and copy/paste to client. But from within app (Powerpoint or Word or Outlook) when Inserting file, the app will hang. Did noot hang when server was not a domain controller. Any ideas on what may be the cause fr this? How to fix? Thanks.