Just tried another clean install myself based on Ubuntu Server 12.04.1, pulling Zentyal in with PPA.
This is really frustrating - a couple of weeks ago I got samba working but couldn't join the domain with my clients, now after a couple of fixes, samba doesn't start anymore. Is this still beta? I followed all instructions in the installation manual.
I'm using the following Zentyal packages:
Core 3.0.7
DNS Service 3.0.2
File Sharing and Domain Services 3.0.9
Users and Groups 3.0.6