ExecJS::ProgramError: [object Object]
from /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/ruby_racer_runtime.rb:49:in `rescue in block in call'
from /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/ruby_racer_runtime.rb:43:in `block in call'
from /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/ruby_racer_runtime.rb:80:in `block in lock'
from /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.10.2/lib/v8/c/locker.rb:13:in `Locker'
from /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/ruby_racer_runtime.rb:78:in `lock'
from /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/ruby_racer_runtime.rb:42:in `call'
from /usr/local/lib/ruby/gems/1.9.1/gems/less-js-0.1.1/lib/less_js.rb:48:in `compile'
from (irb):31
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands/console.rb:47:in `start'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands/console.rb:8:in `start'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:41:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Got a compile error when using 'darken(red, 20%)'