can't run: no method for force_encoding

[mhhf]

trafficstars

I get the following error when i try to run cdnjs list:

/Library/Ruby/Gems/1.8/gems/cdnjs-command-0.0.6/lib/cdnjs_command/package.rb:40:in `fetch': undefined method `force_encoding' for #<String:0x1078069e0> (NoMethodError)
    from /Library/Ruby/Gems/1.8/gems/cdnjs-command-0.0.6/lib/cdnjs_command/package.rb:32:in `all'
    from /Library/Ruby/Gems/1.8/gems/cdnjs-command-0.0.6/bin/cdnjs:23
    from /usr/bin/cdnjs:19:in `load'
    from /usr/bin/cdnjs:19

with ruby --version on OSX 10.8.1:

ruby 1.8.7 (2012-02-08 patchlevel 358) [universal-darwin12.0]

gem --version: 1.3.6 and cdnjs --version:cdnjs-command 0.0.6 Im not a ruby programmer myself, so there might be an error on my side (an installation step I missed?)