I had to fire up Apple's Remote Desktop (ARD) from the other side of the country using ssh. This process is different with ARD 2.1 than it was before -- the pathname is different. So the command to activate is:
/volumes/name_of_disk/System/Library/CoreServices/RemoteManagement/ARDAgent.app\
/Contents/Resources/kickstart -activate -configure -access -on -users admin -privs \
-all -restart -agent -menu
name_of_disk needs to be replaced by the volume name on which the system resides, and admin is the name of the user with admin access. I saw this hint before, but this is the change for the latest ARD.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20041117111532266