I am also having this problem referred to in http://social.technet.microsoft.com/Forums/en/winserversecurity/thread/77150db7-c5d3-472a-b331-e9e71adf519e.
380mb in the Security Log in a single day, the vast majority of which are 538/540 and some 576 success events. Most of the events are from the DC's computer account talking to itself.
Audit Privilege Use is set to failure only.
Looked at the hotfix and it says it only applies to Server 2003 SP1. I am running SP2.
Any ideas?