The problem here can be that the install script is going off to get the Ruby Header files over the web (to build the debugger gem against) but doesn’t find them for the particular patch-level of Ruby you’re after. This is what’s going on in the output line
Looking for http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.2-p14.tar.gz and all I got was a 404! (URI::NotFoundError)
As a solution you can point to your local copy of the Ruby source which rvm has already used to build ruby on your machine. Here goes…
gem install ruby-debug19 -- --with-ruby-include=$rvm_path/src/ruby-1.9.2-head/
Many thanks to Dirk at the following link which helped solve this
- http://dirk.net/2010/04/17/ruby-debug-with-ruby-19x-and-rails-3-on-rvm/