After you install Windows 2003 Service Pack 2 or the SBS 2003 R2 Technologies, you might start seeing some MMC snap-ins displaying an error similar to this:
The source of the problem is that the snap-in is not fully compatible with MMC 3.0, and you most likely have already realized that both Windows 2003 Service Pack 2 and the SBS 2003 R2 Technologies install MMC 3.0.
These are some of the components that you might encounter this problem with:
Health Monitor MMC
Solution: Choose "Continue running and ignore errors with this snap-in for the rest of the session"