Script/console - no such file to load -- readline

Hi there,

I just set up ruby and rails and now whenever I run script/console I get
this error:

Orenad:~/Sway/Projects/mi7/trunk/mi7 dave$ ruby script/console
Loading development environment.
/usr/lib/ruby/1.8/irb/completion.rb:10:in require': No such file to load -- readline (LoadError) from /usr/lib/ruby/1.8/irb/completion.rb:10 from /usr/lib/ruby/1.8/irb/init.rb:218:inrequire’
from /usr/lib/ruby/1.8/irb/init.rb:218:in load_modules' from /usr/lib/ruby/1.8/irb/init.rb:216:ineach’
from /usr/lib/ruby/1.8/irb/init.rb:216:in load_modules' from /usr/lib/ruby/1.8/irb/init.rb:21:insetup’
from /usr/lib/ruby/1.8/irb.rb:54:in `start’
from /usr/bin/irb:13

I installed ruby and rails using darwin ports:

sudo port install ruby
sudo port install rb-rubygems
sudo gem install rails --include-dependencies
sudo ln /opt/local/bin/ruby /usr/local/bin/ruby

Does anyone have any ideas on how to fix this?

Thank you,
Dave