How can I get past “http://gems.rubyforge.org/ does not appear to be a repository” error message

Question

Question 828421 asked similar question, but received only one real answer (update rubygems) and that attempt results in the same error.

Ruby version 1.9.1.p243 on Wi

Answer 1

Sample:

sudo gem install nifty-generators -p http://proxy:port

It works well.