Michael Hartl's Ruby on Rails Tutorial, toy_app user tour

I'm working through Michael Hartl's Ruby on Rails Tutorial and all steps have worked as expected up to the start of section 2.2.1. The first sentence says visiting the root will display the default Rails page. But it doesn't; it shows "hello world" because the tutorial in section 2.1 has us define the root to be application#hello right before deploying to Heroku. If I go to http://localhost:3000/users/, I get an error:

ExecJS::ProgramError in Users#index

Showing C:/Users/dfretz/dfretz/Coursera/Rails_tutorial/toy_app/app/views/layouts/application.html.erb where line #6 raised:

TypeError: Object doesn't support this property or method

Can someone please tell me what I did wrong? Since this is scaffolding-generated code, I don't know how to fix this, or even what files you'd need to see in order to help. Thanks from an obvious newbie.