Error setting up Rails -- Could not find gem "actionview"

I'm not sure why I'm running into this problem as i had previously set up Rails on my Mac successfully. However, I had to set it up again and ran into this error:

ERROR:  Could not find a valid gem 'actionview' (= 4.2.1) in any repository
ERROR:  Possible alternatives: actionview

I tried installing the actionview gem:

gem install actionview

Installation was successful, but I''m still getting the error messages above after running

sudo gem install rails