I've run into some great resources for installing "acts_as_xapian", and the supporting native libraries that are necessary to make it work. I've even got it to work well on my dev machine (OS X).

However, I've followed the instructions on this site, and it doesn't work on my Ubuntu 9.10 (Karmic) production box. After successfully installing the "core" and "bindings" for xapian, the start of the mongrel server fails with the following:

=> Booting Mongrel
=> Rails 2.3.5 application starting on http://0.0.0.0:3000
acts_as_xapian: No Ruby bindings for Xapian installed
/home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:105:in `const_missing': uninitialized constant ActsAsXapian::Search::Xapian (NameError)
 from /var/lib/gems/1.8/gems/acts_as_xapian-0.1.3/lib/acts_as_xapian/search.rb:8
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /var/lib/gems/1.8/gems/acts_as_xapian-0.1.3/lib/acts_as_xapian.rb:2
 from /var/lib/gems/1.8/gems/acts_as_xapian-0.1.3/lib/acts_as_xapian.rb:1:in `each'
 from /var/lib/gems/1.8/gems/acts_as_xapian-0.1.3/lib/acts_as_xapian.rb:1
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/gem_dependency.rb:208:in `load'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:307:in `load_gems'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:307:in `each'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:307:in `load_gems'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:164:in `process'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `send'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `run'
 from /home/feelgoodtrader/feelgoodtrader/config/environment.rb:13
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from /home/feelgoodtrader/.gem/ruby/1.8/gems/rails-2.3.5/lib/commands/server.rb:84
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
 from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
 from script/server:3