2.3 "E: Broken packages"

[newdave]

Trying to install, here's the response:

root@ubuntu-zentyal1:/etc/apt# sudo apt-get install zentyal
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  zentyal: Depends: zentyal-core but it is not going to be installed
           Depends: zentyal-software but it is not going to be installed
E: Broken packages

Here's the pertinent line from sources.list:

# Add repository for Zentyal install
deb http://ppa.launchpad.net/zentyal/2.3/ubuntu precise main

And yes, I've done sudo apt-get update. Any suggestions?