I ran into this problem a day ago: a lot of error messages from repadmin, ntfrsutl, and other utilities on domain controller. Yes, there were some issues over there, however, the biggest issue was that x32 Support Tools were installed on x64 Windows computer.
x32 Support Tools work on x64 machine, but the result is unpredictable. Uninstalling the incorrect version and installing Support Tools from Windows installation CD resolved a half of the issues.
So, be careful, installing Support Tools on x64 Windows