I found some similar problems here on SO, but none seem to match my case (sorry if I overlooked). Here's my problem: I installed oauth-plugin gem to ruby gems dir, but trying to use it in rails app tells me that it's not being found. Here's the output of relevant commands:

Instalation

% s gem install oauth-plugin
Successfully installed oauth-plugin-0.3.14
1 gem installed
Installing ri documentation for oauth-plugin-0.3.14...
Installing RDoc documentation for oauth-plugin-0.3.14...

gem which oauth-plugin output:

% gem which oauth-plugin
/usr/lib/ruby/gems/1.8/gems/oauth-plugin-0.3.14/lib/oauth-plugin.rb

gem env output:

% gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 1.3.6
  - RUBY VERSION: 1.8.7 (2009-12-24 patchlevel 248) [i686-darwin10.2.0]
  - INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: /usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-darwin-10
  - GEM PATHS:
     - /usr/lib/ruby/gems/1.8
     - /Users/eimantas/.gem/ruby/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => true
     - :bulk_threshold => 1000
     - :gem => ["--no-ri", "--no-rdoc"]
     - :sources => ["http://gems.ruby.lt/", "http://rubygems.org/"]
  - REMOTE SOURCES:
     - http://gems.ruby.lt/
     - http://rubygems.org/

Doing ls -l /usr/lib/ruby shows this:

% ls -l /usr/lib/ruby     
lrwxr-xr-x  1 root  wheel  76 Aug 14  2009 /usr/lib/ruby -> ../../System/Library/Frameworks/Ruby.framework/Versions/Current/usr/lib/ruby

And the gem in question is in intended location. This is not a single gem that is not being found by rubygems (although it's located where it should be). Any guidance towards the solution is much appreciated.