Title: 2003 RUS not stamping..ugh
It is not stamping any accounts? Do you see your Exchange Enterprise Servers in the sec tab of your user? Can you also make sure that this group lists all your Exchange servers?
2003, single server, RUS not stamping. Mailbox shows up in the GAL, but no proxies on the object. Rebuilt the RUS, turned up logging on all the important bits and it appears that the RUS is searching and finding changes so I suspect a permissions issue. Any obvious things?