[sudo-users] sudo works for root, not for non-root users

[smitha3 at csusb.edu]

I'm running sudo on about 10 machines with the same configuration.  The
machines are all of the same kind, on 9 of 10 of them, sudo runs as
intended.  however, on the 10th machine, sudo only works for root. 
Non-root users cannot use sudo.  My config looks like this:

User_Alias   ADMINS = admin1, admin2, admin3

Runas_Alias OP = root

root  ALL=(ALL) ALL
ADMINS  ALL=ALL

Its really strange that this machine doesn't allow non-root users to use
sudo, whereas with the same configuration on 9 other machines non-root
users could use sudo just fine.

If anyone has any suggestions on how to make sudo work for all users on
this system, I would appreciate it.
--Aaron Smith