Hello

We recently experienced an issue with our staging server on Heroku. It's the first time we've seen this error and the staging server hasn't been updated in a week or so. It's not clear to me how I should investigate this further so I would appreciate any assistance you might offer. Some details are below:

``` ruby version
ruby 2.0.0p481 (2014-05-08 revision 45883) [x86_64-linux]
```

``` log
2014-07-22T14:47:34.306596+00:00 app[web.2]: /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_request.rb:80:in `parse': method `hash' called on unexpected T_NODE object (0x007fa3c36823d8 flags=0x33b21c) (NotImplementedError)
2014-07-22T14:47:34.306602+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_request.rb:80:in `read'
2014-07-22T14:47:34.306627+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_server.rb:572:in `process_client'
2014-07-22T14:47:34.306629+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_server.rb:666:in `worker_loop'
2014-07-22T14:47:34.306632+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_server.rb:521:in `spawn_missing_workers'
2014-07-22T14:47:34.306653+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_server.rb:532:in `maintain_worker_count'
2014-07-22T14:47:34.306657+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/lib/unicorn/http_server.rb:290:in `join'
2014-07-22T14:47:34.306658+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/gems/unicorn-4.8.2/bin/unicorn:126:in `<top (required)>'
2014-07-22T14:47:34.306659+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/bin/unicorn:23:in `load'
2014-07-22T14:47:34.306660+00:00 app[web.2]:    from /app/vendor/bundle/ruby/2.0.0/bin/unicorn:23:in `<main>'
2014-07-22T14:47:34.461811+00:00 app[web.2]: E, [2014-07-22T14:47:34.461628 #2] ERROR -- : reaped #<Process::Status: pid 122 exit 1> worker=0
```

Cheers
Philip