I also followed the instructions of the blog post you mentioned, and
also got the same results. The gem I'm using is the "stanfordparser"
v2.2.0 (https://github.com/jcwilk/stanfordparser)

From the changelog at the Stanford Parser website, I figured the last
version (1.6.6) changed APIs that the ruby wrapper does not understand.

---
Version 1.6.6  2011-04-20   Internal code and API changes (ArrayLists
rather than Sentence; use of CoreLabel objects) to match tagger and
CoreNLP.
---

So, I tried the previous version, which is available at.

http://nlp.stanford.edu/software/stanford-parser-2010-11-30.tgz

I got it to work with this version, but I could not make the simple test
work:

ruby-1.8.7-p334 :003 > require 'stanfordparser'
 => true
ruby-1.8.7-p334 :004 > preproc =
StanfordParser::DocumentPreprocessor.new
 => <DocumentPreprocessor>
ruby-1.8.7-p334 :005 > puts preproc.getSentencesFromString("This is a
sentence.  So is this.")
This
is
a
sentence
.
So
is
this
.
 => nil


I got the StanfordParser::LexicalizedParser, but not the
DocumentPreprocessor, which was also what I was hoping to use.

I also installed the gem "stanfordparser-infochimps", version 2.2.2
(https://github.com/mrflip/stanfordparser), instead of the 2.2.0 version
above, and got the same results.

Did you have made any further progress than this?

-- 
Posted via http://www.ruby-forum.com/.