When you installed ubuntustudio-installer from the command line, it should have pulled-in ubuntustudio-controls which pulls-in jackd2. Installer should not have had to install jackd2 at all, so this shows me that you installed ubuntustudio-installer without any of its dependencies. That's why it's stalled.
I see that the ubuntustudio-installer has been updated so that jackd2 and a number of other dependencies now get pulled in when the ubuntustudio-installer is installed, so that they are loaded prior to running the ubuntustudio-installer. A bit of a kludge, but it worked when I tried it.
When you installed ubuntustudio-installer from the command line, it should have pulled-in ubuntustudio-controls which pulls-in jackd2. Installer should not have had to install jackd2 at all, so this shows me that you installed ubuntustudio-installer without any of its dependencies. That's why it's stalled.
I see that the ubuntustudio-installer has been updated so that jackd2 and a number of other dependencies now get pulled in when the ubuntustudio-installer is installed, so that they are loaded prior to running the ubuntustudio-installer. A bit of a kludge, but it worked when I tried it.