Thread error "undefined method `keys' for nil:NilClass"

Hi all I have this prog taken from a book.

require ‘net/http’

pages = [“www.rubycentral.com”, “www.awl.com”, “www.davidecasale.com”]

threads = []

pages.each do |page|
threads << Thread.new(page) { |myPage|

h = Net::HTTP.new(myPage, 80)
puts "Fetching: #{myPage}"
resp, data = h.get('/', nil )
puts "Got #{myPage}:  #{resp.message}"

}
end

but when i run it It gives me this error.

/usr/local/lib/ruby/1.9.1/net/http.rb:809:in get': undefined methodkeys’ for nil:NilClass (NoMethodError) from Threads.rb:19:in `block (2
levels) in ’

It’s weird because it’s working on ruby 1.8.7