Railties Name Error on production deployment

Question

I'm in the process of deploying my application to production (well, attempting to at least). I keep running into this error:

/opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/wicked_pdf-0.11.0/lib/wicked_pdf/railtie.rb:6:in `<top (required)>': uninitialized constant Rails::VERSION (NameError)
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/wicked_pdf-0.11.0/lib/wicked_pdf.rb:27:in `require'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/wicked_pdf-0.11.0/lib/wicked_pdf.rb:27:in `<top (required)>'
    from /opt/www/sunstar/releases/20150325005143/config/application.rb:2:in `require'
    from /opt/www/sunstar/releases/20150325005143/config/application.rb:2:in `<top (required)>'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:141:in `require'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:141:in `require_application_and_environment!'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:67:in `console'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /opt/www/sunstar/shared/bundle/ruby/2.1.0/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

Anyone have experience with this error? I'm using railties 4.2.0 and I see 4.2.1 is out but not sure if I should do update or roll back.