Facebooker error?

I installed the facebooker plugin and now I’m getting this error but
not sure what it means…

/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require': no such file to load -- json (MissingSourceFile) from /usr/local/lib/site_ruby/1.8/rubygems/ custom_require.rb:27:inrequire’ from /usr/lib/ruby/gems/1.8/gems/
activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require' from /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/ active_support/dependencies.rb:342:innew_constants_in’ from /usr/lib/
ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/
dependencies.rb:496:in require' from /mnt/home/userapps/11561/vendor/ plugins/facebooker/lib/facebooker.rb:1 from /usr/local/lib/site_ruby/ 1.8/rubygems/custom_require.rb:27:ingem_original_require’ from /usr/
local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in require' from /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/ active_support/dependencies.rb:496:inrequire’ … 23 levels… from /
usr/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/generate.rb:1
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' from /usr/local/lib/site_ruby/1.8/rubygems/ custom_require.rb:27:inrequire’ from script/generate:3