Why can’t I install MMC?

When I try to install Microsoft Management Console (MMC) it appears to finish ok, but when I run MMC.exe I get this message:
“MMC cannot create a node manager. Make sure the file Mmcndmgr.dll is registered.”

I need MMC to work so that I can install NAV Corporate Edition.

The system I’m installing onto is running NT 4.0(SP6a).