Mattia, I've bumped my head a lot on openacs installed by Debian packages and really, it's not worth the effort. It's not that they don't work, they somehow do, but there is a lot of tweaking needed to have a properly configured instance, so that the main purpose of the package is nullified. Also, you are getting software like 5 years old now and sometimes this is noticeable.
As Gustaf suggested, try installation scripts found at
https://openacs.org/xowiki/naviserver-openacs
They assume Debian/Ubuntu as distro, so they should be perfectly suitable to your requirements, and they are also very easy to use.
For assistance you can ask here and I will gladly help you.
Ciao
