Some of you may find that MEP .NET samples do not compile because the references to the AecArchMgd.dll and AecBaseMgd.dll assemblies could not be found.
You will find these assemblies (as well as other ACA specific assemblies) in the subfolder <AutoCAD MEP Install Folder>\ACA.
You will also find MEP specific assemblies in the subfolder <AutoCAD MEP Install Folder>\MEP.