I have installed first webmin and after virtualmin on centos;
in the demo I noticed that virtualmin have a tab link at the top of the sidebar near the webmin’s tab;
in my case I not have this tab; I have only webmin and regards virtualmin have only a link under Webmin-> Servers;
I have so only this menu’s voice: Virtualmin Virtual Servers (GPL);
How can resolve?
Howdy,
If you didn’t use the install.sh script to install Virtualmin, I’d highly recommend doing so – that’ll save you a lot of time 
You can find that by going to the “Downloads” link above.
Otherwise, you would want to follow the manual installation instructions here:
http://www.virtualmin.com/documentation/installation/manual
It sounds like you’re missing some packages though… what you’re seeing could happen if you’re missing the Virtualmin theme.
-Eric
infact theme solved thanks