Problema con RoR y Oracle

[jasv]

Estoy instalando una aplicación hecha sobre RoR en mi máquina que tiene Ubuntu Jaunty, ya instalé Ruby, Rails, las gemas, el adaptador OCI8 (el cual también probé por consola y funciona). Pero cuando corro: "ruby script/server", me sale éste error:

Código:

/usr/local/lib/site_ruby/1.8/rubygems.rb:270:in `activate': undefined method `map' for nil:NilClass (NoMethodError)
	from /usr/local/lib/site_ruby/1.8/rubygems.rb:296:in `activate'
	from /usr/local/lib/site_ruby/1.8/rubygems.rb:295:in `each'
	from /usr/local/lib/site_ruby/1.8/rubygems.rb:295:in `activate'
	from /usr/local/lib/site_ruby/1.8/rubygems.rb:68:in `gem'
	from /opt/redmine/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb:226:in `establish_connection'
	from /opt/redmine/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb:216:in `establish_connection'
	from /opt/redmine/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb:209:in `establish_connection'
	from ./script/../config/../vendor/rails/railties/lib/initializer.rb:341:in `initialize_database'
	from ./script/../config/../vendor/rails/railties/lib/initializer.rb:124:in `process'
	from ./script/../config/../vendor/rails/railties/lib/initializer.rb:97:in `send'
	from ./script/../config/../vendor/rails/railties/lib/initializer.rb:97:in `run'
	from /opt/redmine/config/environment.rb:20
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:355:in `new_constants_in'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
	from /opt/redmine/vendor/rails/railties/lib/commands/servers/webrick.rb:59
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:355:in `new_constants_in'
	from /opt/redmine/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
	from /opt/redmine/vendor/rails/railties/lib/commands/server.rb:39
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from script/server:3

La base de datos se encuentra en otra máquina. Probé con un comando similar a éste y funcionó:

Código:

ruby -r oci8 -e "OCI8.new('hr', 'hr_password', 'ORCL').exec('SELECT * FROM jobs
ORDER BY 1') do |r| puts  r.join(' | '); end"

Soy muy nuevo en Ruby On Rails, espero me puedan guiar para solucionar éste problema... saludos.