Installing lxml module in python
Just do:
sudo apt-get install python-lxmlFor Python 2 (e.g., required by Inkscape):
sudo apt-get install python2-lxmlIf you are planning to install from source, then albertov's answer will help. But unless there is a reason, don't, just install it from the repository.
You need to install Python's header files (python-dev package in debian/ubuntu) to compile lxml. As well as libxml2, libxslt, libxml2-dev, and libxslt-dev:
apt-get install python-dev libxml2 libxml2-dev libxslt-dev