I’m installing MOM on a Windows 2000 Server. I’ve installed Active Directory and SQL 2000 and run the Prerequisite checker OK but when I select to install all components I get the following message:

"Setup has detected that you are attempting to install Microsoft Operations Manager on a domain controller. Installing the database, DAS, Consolidator, or Agent Manager on a Domain Controller might not function properly and is not supported. Please select a different option of installation."

From the microsoft.public.mom newsgroup
One of the reasons that this configuration is not supported is that the DCAM and database in MOM can put a high load on your CPU and memory resources during some of its operations. This can cause authentications to your DC to fail or hang. This will in turn cause alerts to flood MOM, which takes the CPU higher, which... well, you get the picture.

You can install the DCAM and DB on another server and install only the agent on the DC. There is great information in both the MOM Operations Guide and the Installation docs on the Microsoft web site that can help clarify installation, etc.

Installing SQL Server or Exchange on a DC isn't a good idea for these reasons.