railsコマンド全般のエラーに関して

質問失礼いたします。

railsコマンド全般でエラーが出てしまうのですが、原因がわかりません。
rails sコマンド後に以下の様なエラーを吐き出し、立ち上がりません。
他のファイル等は全くいじっていないので、Psych::SyntaxErrorなども心当たりがない状況です。

ちなみに
ruby 2.0.0p645 (2015-04-13 revision 50299) [x86_64-darwin15.0.0]
Rails 4.2.4
を利用しております。

何か解決策があれば教えていただけると嬉しいです。

=> Booting WEBrick
=> Rails 4.2.4 application starting in development on http://localhost:3000
=> Run rails server -h for more startup options
=> Ctrl-C to shutdown server
Exiting
/Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/psych.rb:205:in parse': (<unknown>): did not find expected alphabetic or numeric character while scanning an alias at line 26 column 20 (Psych::SyntaxError) from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/psych.rb:205:in parse_stream'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/psych.rb:153:in parse' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/psych.rb:129:in load'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/application.rb:391:in secrets' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/application.rb:178:in key_generator'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/application.rb:206:in message_verifier' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/globalid-0.3.6/lib/global_id/railtie.rb:25:in block (2 levels) in class:Railtie'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/activesupport-4.2.4/lib/active_support/lazy_load_hooks.rb:36:in call' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/activesupport-4.2.4/lib/active_support/lazy_load_hooks.rb:36:in execute_hook'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/activesupport-4.2.4/lib/active_support/lazy_load_hooks.rb:45:in block in run_load_hooks' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/activesupport-4.2.4/lib/active_support/lazy_load_hooks.rb:44:in each'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/activesupport-4.2.4/lib/active_support/lazy_load_hooks.rb:44:in run_load_hooks' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/application/finisher.rb:62:in block in module:Finisher'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/initializable.rb:30:in instance_exec' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/initializable.rb:30:in run'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/initializable.rb:55:in block in run_initializers' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:150:in block in tsort_each'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:183:in block (2 levels) in each_strongly_connected_component' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:219:in each_strongly_connected_component_from'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:182:in block in each_strongly_connected_component' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:180:in each'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:180:in each_strongly_connected_component' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/2.0.0/tsort.rb:148:in tsort_each'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/initializable.rb:54:in run_initializers' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/application.rb:352:in initialize!'
from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/config/environment.rb:5:in <top (required)>' from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/config.ru:3:in require'
from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/config.ru:3:in block in <main>' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in instance_eval'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in initialize' from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/config.ru:in new'
from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/config.ru:in <main>' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in eval'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in new_from_string' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:40:in parse_file'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:299:in build_app_and_options_from_config' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:208:in app'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/server.rb:61:in app' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:336:in wrapped_app'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/server.rb:139:in log_to_stdout' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/server.rb:78:in start'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:80:in block in server' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:75:in tap'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:75:in server' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:39:in run_command!'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/railties-4.2.4/lib/rails/commands.rb:17:in <top (required)>' from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/bin/rails:9:in require'
from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/bin/rails:9:in <top (required)>' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/client/rails.rb:28:in load'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/client/rails.rb:28:in call' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/client/command.rb:7:in call'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/client.rb:28:in run' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/bin/spring:49:in <top (required)>'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/binstub.rb:11:in load' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/gems/2.0.0/gems/spring-1.6.2/lib/spring/binstub.rb:11:in <top (required)>'
from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:54:in require' from /Users/co_jp_ta/.rbenv/versions/2.0.0-p645/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:54:in require'
from /Users/co_jp_ta/projects/ruby-2.0.0/retwetter/bin/spring:13:in <top (required)>' from bin/rails:3:in load'
from bin/rails:3:in `<main>'