Hi Danilo,
Are you using the "release" package or "sourcecode"?
If you are hosting multiple sites, then when you create a new site from the root admin site, it does not install all the features in the new site by default. If you go into Site Settings on the root admin site and choose the child site from the dropdown, there is a tab there where you can add or remove features in a child site.
Hope it helps,
Joe