Cannot use ppa to install repositories

[Lihuel]

I am a new user at Linux. I do not understand very much about this. I tryed to install one of the elementary apps, which was elementary tweaks. I had been looking in the internet that the only way to do this is by ppa and repositories and things like that. So here is the thing: when I try to do that this is the answer:
lihuel97@MiEquipo:~/Documents$ sudo add-apt-repository ppa:mpstark/elementary-tweaks-daily
[sudo] password for lihuel97:
Traceback (most recent call last):
  File "/usr/bin/add-apt-repository", line 91, in <module>
    sp = SoftwareProperties(options=options)
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 109, in __init__
    self.reload_sourceslist()
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 599, in reload_sourceslist
    self.distro.get_sources(self.sourceslist)
  File "/usr/lib/python3/dist-packages/aptsources/distro.py", line 89, in get_sources
    (self.id, self.codename))
aptsources.distro.NoDistroTemplateException: Error: could not find a distribution template for Ubuntu/n/a

As you may imagine I did not understand anything of this, so I copied this on the internet and I did not found any solutions so that is why I am asking you what to do. Maybe there is not a solution yet. I can accept that, but please tell me how could I install elementary tweaks or any other ppa.
Some extra info: I found in the internet that I should edit a document called lsb-release from the folder /etc/. So I edited some info there and this is how it is right now:
DISTRIB_ID="elementary OS"
DISTRIB_RELEASE=0.3.2
DISTRIB_CODENAME=freya
DISTRIB_DESCRIPTION="elementary OS Freya"

Another extra data: I also found that it maybe useful to upgrade something called canberra with sudo apt-get install libcanberra-gtk-module:i386. Of course it was useless for two reasons: the first one, this did not work; and the second one if i try install libcanberra-gtk-module it installs something but it does not solve the problem. Greetings from Argentina and thanks for read.

[Leonardo Lemos (leonardolemos)]

Marking it as invalid since it's not a bug, just a support request.

[Leonardo Lemos (leonardolemos)]

My personal advice: try to search how to add ppas through the software center.