With debian 10 there are some problems installing Plone-4.3.x.
With Ubuntu 16.04.4 LTS there are problems with Plone-4.3.4-UnifiedInstaller
There is a modified (r1) Plone-4.3.4-r1-UnifiedInstaller. This might help in your use case.
Use as follows in Ubuntu 16.04.4 LTS:
sudo apt-get update
sudo apt-get install -y build-essential libjpeg-dev libjpeg-dev libreadline-dev \
libssl-dev libxml2-dev libxml2-dev libxslt1-dev libxslt1-dev poppler-utils \
python-dev wv zlib1g-dev vim-nox
------------------------------------------------------------
cd ~
wget -O ~/Plone-4.3.4-r1-UnifiedInstaller.tgz \
https://launchpad.net/plone/4.3/4.3.4/+download/Plone-4.3.4-r1-UnifiedInstaller.tgz
cd ~
tar xzf Plone-4.3.4-r1-UnifiedInstaller.tgz
cd ~/Plone-4.3.4-UnifiedInstaller
sudo ./install.sh --target=/home/Plone-4.3.4 --instance=zeocluster \
--clients=2 --daemon-user=plone_daemon --owner=plone_buildout --group=plone_group \
--build-python --password=admin --libjpeg=yes zeo
------------------------------------------------------------
sudo -u plone_buildout /home/Plone-4.3.4/zeocluster/bin/buildout \
-c /home/Plone-4.3.4/zeocluster/buildout.cfg