Problems getting Rails running on Mac OSX Snow Leopard - ruby-on-rails

Question

Update and Solution
I finally got everything working after
1. Uninstalling everything ruby-related in /usr/local/... as well as uninstalling all versions of rails.
2. Installing RVM as a standard user -> i.e. installed in my home directory and NOT in /usr/local as root
3. rvm install 1.8.7 and set as default
Now everything seems to be working fine.
My conclusion after days of googling and reading about others' solutions is that Snow Leopard just doesn't handle the rails dev environment well unless you sandbox it through RVM in a local director. I resisted going to RVM because I don't have a need to manage multiple ruby versions.
Some of the responses below along with my code excerpts on pastie may provide some helpful advice for others trying to troubleshoot. In particular from #fl00r and #Kelvin:
run which -a for gem, bundle, rails, rake, etc. to see the available versions. Check to see which versions of ruby are being called with head -1 on each.
Original Below
Pretty much at my wit's end after a few days of Googling, uninstalling, and re-installing. I'm trying to get rails running on Mac OS X 10.6.7. I followed the Hivelogic Post on this topic. Apologize for the length of this question.
Has anyone followed a step-by-step uninstall/reinstall process for getting this working? Or a link to advice on troubleshooting? Should I clean out everything following this advice from Chad Wooley and migrate to RVM?
The common theme has been errors related to being unable to find gems even though they are installed. For instance, trying to create a new rails app:
kevindewalt#new-host-4:~/Documents$ $ rails new blog
You don't have i18n installed in your application. Please add it to your Gemfile and run bundle install
Or an existing app I have running on another machine after running bundle install:
kevindewalt#new-host-4:~/Documents/ClaimAway$ (master) $ rake db:setup
(in /Users/kevindewalt/Documents/ClaimAway)
Could not find i18n-0.4.2 in any of the sources
Try running `bundle install`.
kevindewalt#new-host-4:~/Documents/ClaimAway$ (master) $ rails s
/usr/local/lib/ruby/gems/1.8/gems/actionpack-3.0.0/lib/action_dispatch.rb:35:in `require': no such file to load --
-
kevindewalt#new-host-4:~/Documents$ $ gem env
RubyGems Environment:
- RUBYGEMS VERSION: 1.7.2
- RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin10.7.0]
- INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8
- RUBY EXECUTABLE: /usr/local/bin/ruby
- EXECUTABLE DIRECTORY: /usr/local/bin
- RUBYGEMS PLATFORMS:
- ruby
- x86-darwin-10
- GEM PATHS:
- /usr/local/lib/ruby/gems/1.8
- /Users/kevindewalt/.gem/ruby/1.8
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- http://rubygems.org/
-
kevindewalt#new-host-4:~/Documents$ $ echo $PATH
/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:/opt/local/bin:/opt/local/sbin:/usr/local/git/bin:/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
-
kevindewalt#new-host-4:~/Documents$ $ which -a ruby
/usr/local/bin/ruby
/usr/local/bin/ruby
/usr/bin/ruby
/usr/local/bin/ruby

Answer 1

add to Gemfile
gem 'i18n'
Actually you should specify exact version also:
gem 'i18n', '0.4.2'
then run bundle install. But as far your i18n gem will be locked try this:
bundle update i18n
That is all what is written in your error.

Answer 2

rvm is probably your best bet to prevent problems like this. But it might be overkill if you actually don't need multiple ruby version or gemsets.
Let me try to diagnose the issue. If we can solve it, then you don't have to jump through the rvm hoops (unless you want to of course).
I suspect that when you run some of these ruby-based scripts like 'gem', 'bundle', 'rails', and 'rake' the shebang line of these scripts is pointing to a ruby installation that you didn't expect.
Here's my usual checklist of diagnosing gem issues like this.
Run "which -a gem". Do you see multiple unique locations? If so, gem list using the full path to gem. E.g. "/usr/bin/gem list" and "/usr/local/bin/gem list". My guess is that you'll see that one of the lists has i18n and the other doesn't.
Run "which" on rails, bundler, and gem. Run "head -1" on each of those paths. Does the ruby path match in all of them?
My guess is that the "rails" in your PATH is not using the same ruby as the "gem" in your PATH. Maybe you installed it with the preinstalled 'gem' command so it's pointing to the system ruby's gem directory rather than /usr/local. Try reinstalling rails, then closing and reopening your terminal. Then use the "which" and "head -1" above to make sure "rails" is using the same ruby as "gem" is.
Another suspect is the "sudo" command. You may also want to run the "which" command via sudo, e.g. sudo sh -c 'which gem'. It's possible that sudo is running one of the preinstalled scripts.
If in doubt, you could run: "sudo /usr/local/bin/gem install rails" so you know for sure which gem command you're using.

Answer 3

I would do a couple of things.
Start by uninstalling Rails >= 3 from your current systems gem installation. This includes all Rails dependencies. You should be able to boot < Rails3 projects using your normal gem installation now.
Next up install rvm and use rvm to install Ruby 1.9.2 and Rails3. Use the 1.9.2 rvm to work with your Rails3 projects. Part of rails3 and rails2 don't work well together so you should always try to seperate them imho.

Answer 4

See this stack question for step by step instructions for installing rails using rvm. This is the most tried and true method I've found:
Uninstall Ruby on Rails on Mac OS X 10.6