trouble initiating graph

HI there,

I already posted this question on stack overflow (http://stackoverflow.com/questions/28016297/trouble-initializing-graph-new-using-ruby-rdf-rb-gem), but I wasn’t getting any help.

I wonder if anyone can help me with the following problem.

I am trying to intitialize a graph following the documentation for the ruby RDF gem. (http://www.rubydoc.info/gems/rdf/RDF/Graph)

Documentation provides the following example:

graph = Graph.new("http://rubygems.org/")

I've tried to run this exact command and I get an error (which I don't really understand). (Note that I have successful loaded a graph when using a file from my local machine, so I think there is some trouble with the attempt to load a graph from an http url.)

I'm running the command through the command line interface Gem Thor. Below is the executable file and then the error returned.

file lbp

#!/usr/bin/env ruby

require 'rdf'
require 'rdf/rdfxml'
require 'rdf/ntriples'
require 'thor'
require 'pry'

class LbpCli < Thor
  desc "hello", "say hello to NAME"
  def hello(name)
      puts "Hello #{name}!"
  end

  desc "init", "create projectifles dirs in current working directory"
  def init(dir="projectfiles")
      directories = ["#{dir}/Conf", "#{dir}/Textfiles", "#{dir}/citationlists"]
      FileUtils.mkpath(directories)
  end

  desc "projecfile", "make projetfile from SCTA"
  def projectfile
      graph = RDF::Graph.new("http://rubygems.org")
  end
end

LbpCli.start(ARGV)

projectfile is the relevant method. Below is the command run and the error returned.

file lbp run with method projectfile

$ ./lbp projectfile
/Users/JCWitt/.rvm/gems/ruby-2.2.0@lbp/gems/rdf-1.1.7/lib/rdf/model/graph.rb:126:in `initialize': Can't apply context unless initialized with `data` supporting contexts (ArgumentError)
    from ./lbp:28:in `new'
    from ./lbp:28:in `projectfile'
    from /Users/JCWitt/.rvm/gems/ruby-2.2.0@lbp/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    from /Users/JCWitt/.rvm/gems/ruby-2.2.0@lbp/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    from /Users/JCWitt/.rvm/gems/ruby-2.2.0@lbp/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
    from /Users/JCWitt/.rvm/gems/ruby-2.2.0@lbp/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    from ./lbp:45:in `<main>'

Thanks for any help you can provide,
jeff