NoMethodError: undefined method `value' for nil:NilClass

[brundage]

0 HAL:0 work % irb
1.9.3p0 :001 > require 'quantity'
 => true 
1.9.3p0 :002 > q = Quantity.new(1, 'ml')
NoMethodError: undefined method `value' for nil:NilClass
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:297:in `block (2 levels) in calculate_value'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:295:in `times'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:295:in `block in calculate_value'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:294:in `each'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:294:in `calculate_value'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:279:in `initialize'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:256:in `new'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity/unit.rb:256:in `from_string_form'
    from /home/brundage/.rvm/gems/ruby-1.9.3-p0/gems/quantity-0.1.2/lib/quantity.rb:79:in `initialize'
    from (irb):2:in `new'
    from (irb):2
    from /home/brundage/.rvm/rubies/ruby-1.9.3-p0/bin/irb:16:in `<main>'