Thanks for reporting this! It looks like an error with the
pocketsphinx-ruby gem, which is under pretty active development. I know I had issues with version 0.2, which is why the Gemfile is locked at 0.1.1, but it looks like 0.3 is out now, which may be worth checking out. Can you try updating to 0.3 and see if that fixes the error for you? If it does, I'll experiment and consider updating here.
If it doesn't, I would open up an issue at
pocketsphinx-ruby. The owner of that gem has been very responsive in my experience.
Either way, please let me know what you end up doing so I'll know whether to close this issue or not.