My hosted VPS server is based on Virtuozzo. When it was initially provided, I could access the Parallels Power Panel. When it was migrated to Ubuntu, it would no longer authenticate me with my root password.
I wonder if it is a groups/permissions issue.
(In my understanding, there is a clash of levels here - how can Power Panel use the root password of the very machine it is designed to manage? If my machine has hung, how can it read the password to reset it? I am obviously missing something.)
Power panel adjusts the parameters through an app called vzagent0 and that is the control interface between the power panel and the VPS. That is to make sure you can manage services and templates for which you might need root or su permissions.
However I strongly advise not to use root as account but rather create a sudoer to your needs and make sure you never permit root logon for ssh.
this one is probably either resolved or forgotten by now, but just in case anyone has the same problem - if it is Ubuntu and Power Panel problem in Virtuozzo then it is probably explained here