SySE is a syntactic sentence extracter based on pystatparser, which in turn is based on nltk. nltk is not available on Windows systems, therefore, this program is not expected to work on them.
It can be found on github here: https://github.com/NathanWycoff/SySE
You can reach its author, Nathan Wycoff, at nathanbrwycoff@gmail.com

You can find a lot more information about how it works here:
http://frequentlybayesian.blog.com/2016/01/14/synactic-sentence-extraction-syse/

!!!!NOTICE!!!!!
In its current form, this program will NOT work in an environment that has nltk in it as well. If you have nltk on your system, please create a virtual environment which does not see it in order to run SySE.
I apologize for the inconvenience, and will publish a fix soon.

***Installation:
You must first download pystatparser:
pip install --upgrade https://github.com/emilmont/pyStatParser/tarball/master

Then you can install SySE:
pip install --upgrade https://github.com/NathanWycoff/SySE/tarball/master

Useage:
from syse import SySE
sy = SySE()

#If you don't get a warning, you're good to go!
#You can get a probability on a single sentence using:
sy.classify("This is an important sentence")

#Summarize an article (str or unicode) stored in myArticle
sy.summarize(myArticle)

#Otherwise, SySE may have been unable to load the default parameters,
called "default.dat". This should have automatically downloaded to
#The distribution where SySE is installed (try syse.__file__ in the interpreter with SySE loaded).
#Download or locate it, then load it manually using:
sy.loadParameters('path/to/default.dat')

#Otherwise, you can train on a dataset yourself.
sy.train(trainingSentences, importanceLabels)

#The dataset used for default parameters can be found on the github.