not running on primary?

Installed and activated Multiplicity 1.21 (by copying sig.bin into directory) on primary and secondary (both Win XP), ran wizards on both, rebooted machines. The secondary came up fine with the box saying Mult. is running. The primary came up with nothing, no box, not in systray. When you click on the shortcut in the Start menu, nothing happens. When I manually start the service in services, nothing happens. Uninstalled and reinstalled on the primary with exactly the same problem. What's up?