You need some supporting software in Ubuntu. This is probably not a complete list, but at least you need:
apt-get install python-virtualenv python-dev libxslt1-dev libxml2-dev build-essential
ln -s /usr/include/libxml2/libxml/ /usr/include/libxml
Now create the virtualenv and install stuff:
virtualenv create ~/drm_python
source ~/drm_python/bin/activate
pip install -r drm.reqs
Now run the server:
python server.py 31337
The client then runs as:
python client.py localhost 31337 "my book"
A book's hash can be verified by doing:
echo -n "This is our secret watermark for THE_BOOK_TITLE" | md5sum