LoadError in Ubuntu Lucid

After running sudo gem install adhearsion, executing ahn -h gives me:

/usr/bin/ahn:19:in `load': no such file to load -- /usr/lib/ruby/gems/1.8/gems/adhearsion-0.8.5/bin/ahn (LoadError) from /usr/bin/ahn:19

I'll try to give as many other relevant details as possible. I have created this error on two separate machines running the same versions of Ubuntu (Ubuntu Lucid). The first machine used Adhearsion's installation process to a tea, except instead of apt-get I used aptitude. The second Ubuntu install had rubygems compiled from source, but everything else installed from aptitude.

ruby -v
ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux]

gem -v
1.3.7

Additionally, if I attempt to install adhearsion again:

sudo gem install adhearsion
Successfully installed adhearsion-0.8.5
1 gem installed

And lastly:

irb
irb(main):001:0> require 'rubygems'
=> true
irb(main):002:0> require 'adhearsion'
LoadError: no such file to load -- adhearsion

    from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
    from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from (irb):2
    from :0

irb(main):003:0>