cannot load such file -- wiringpi (LoadError) with RubyDev installed

[alistairbill]

When running the following Ruby file as root:

#!/usr/bin/env ruby

require 'wiringpi'
io = WiringPi::GPIO.new(WPI_MODE_GPIO)
pin = 18
range = (15..255).to_a
range += range.reverse

def sleep_func(i)
  sleep(0.004) if (i > 150)
  sleep(0.005) if (i > 125) &&  (i < 151)
  sleep(0.007) if (i > 100) &&  (i < 126)
  sleep(0.010) if (i > 75)  &&  (i < 101)
  sleep(0.014) if (i > 50)  &&  (i < 76)
  sleep(0.018) if (i > 25)  &&  (i < 51)
  sleep(0.019) if (i > 1)   &&  (i < 26)
end

loop do 
  range.each do |i|
    io.pwmWrite pin, ((i/255.0) * 1000).to_i
    sleep_func i
  end

  sleep 1
end

I get this error:

/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in 'require': cannot load such file -- wiringpi
(LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in 'require' 
from ./pulse.rb:3:in '{main}' 

The squiggly brackets are <>. The markdown didn't like them, hehe. I read Gadgetoid's issue and dutifully installed ruby-dev, but the same error still occurs. Not sure if it's bad coding, bad installing or something else. I'm a bit of a 'Ruby Newby', so please forgive me if I'm being stupid :)

[alistairbill]

My apologies, I was running the gem on my Ruby 1.9.3 but the interpreter was 1.9.1. Everything is now sorted... sorry!