Q:

Receiving syntax error message when trying to start application server for first Rails application after configuration [noob]

The following message pops up when I enter $ rails server in the Terminal (Mac, running latest version of Yosemite). I'm pretty lost, other topics have recommended altering the text in the config folder of my project, but what I've tried hasn't worked and I'm guessing because those are slightly dated topics. 
I'm learning from the Learn Ruby on Rails book trying to get this MailChimp application working, completed up to the 13th chapter without any big issues. Any help is appreciated.
=> Booting WEBrick
=> Rails 4.1.1 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--     binding option)
=> Ctrl-C to shutdown server
Exiting
/Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/psych.rb:370:in `parse':     (<unknown>): found character that cannot start any token while scanning for the next token     at line 14 column 1 (Psych::SyntaxError)
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/psych.rb:370:in `parse_stream'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/psych.rb:318:in `parse'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/psych.rb:245:in `load'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/application.rb:313:in `secrets'
from /Users/dengel29/workspace/learn-rails/config/environments/development.rb:32:in `block in <top (required)>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/railtie.rb:210:in `instance_eval'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/railtie.rb:210:in `configure'
from /Users/dengel29/workspace/learn-rails/config/environments/development.rb:1:in `<top (required)>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `block in require'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:232:in `load_dependency'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/engine.rb:594:in `block (2 levels) in <class:Engine>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/engine.rb:593:in `each'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/engine.rb:593:in `block in <class:Engine>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:30:in `run'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:418:in `block (2 levels) in each_strongly_connected_component_from'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:417:in `block in each_strongly_connected_component_from'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:44:in `each'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:44:in `tsort_each_child'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:411:in `call'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:411:in `each_strongly_connected_component_from'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `each'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `call'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
from /Users/dengel29/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/application.rb:288:in `initialize!'
from /Users/dengel29/workspace/learn-rails/config/environment.rb:5:in `<top (required)>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `block in require'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:232:in `load_dependency'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/dengel29/workspace/learn-rails/config.ru:3:in `block in <main>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
from /Users/dengel29/workspace/learn-rails/config.ru:in `new'
from /Users/dengel29/workspace/learn-rails/config.ru:in `<main>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/server.rb:50:in `app'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/server.rb:130:in `log_to_stdout'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/server.rb:67:in `start'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:81:in `block in server'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:76:in `tap'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:76:in `server'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/railties-4.1.1/lib/rails/commands.rb:17:in `<top (required)>'
from /Users/dengel29/workspace/learn-rails/bin/rails:8:in `require'
from /Users/dengel29/workspace/learn-rails/bin/rails:8:in `<top (required)>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `load'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `call'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/client.rb:26:in `run'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/bin/spring:48:in `<top (required)>'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `load'
from /Users/dengel29/.rvm/gems/ruby-2.1.1/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `<top (required)>'
from /Users/dengel29/workspace/learn-rails/bin/spring:16:in `require'
from /Users/dengel29/workspace/learn-rails/bin/spring:16:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'

A:

Perhaps your ENV variables are not set up correctly, or you have an unusual character in one of the variables. Be careful there are not tab characters or any unusual characters in the config/secrets.yml file.
I suggest you replace all ENV values in the config/secrets.yml with hardcoded strings. Don't check the file into git with your private credentials in the file. Just test it to see if you can isolate the problem.

