HUBzero makes extensive use of OpenVZ containers so it is recommended to use the OpenVZ enabled kernel on all HUBzero servers.
# apt-get install hubzero-openvz
# hzcms configure openvz --enable
If configuration is successful it should prompt you to reboot the server to activate the new kernel.
# vzlist Container(s) not found
Or it will list the containers currently running if you check this on a running hub. The salient point being that the command doesn't issue any kind of error message.