I'm on Max OS 10.5 and using rvm to handle more Ruby versions.
I have the ruby-1.8.6 below selected under settings - ruby versions and in that same place the rails 1.2.3 gem also appears.
mongrel_rails starts without problems from terminal (from /Users/mb/Rapidi2)
yet it fails to start from within RubyMine (see error message below)
/Users/mb/.rvm/ruby-1.8.6-p383/bin/ruby /Users/mb/Rapidi2/script/server mongrel -p 8090 -b 0.0.0.0 -e development
Cannot find gem for Rails =1.2.3:
Install the missing gem with 'gem install -v=1.2.3 rails', or
change environment.rb to define RAILS_GEM_VERSION with your desired version.
thanks for any help