Rubygems. LoadError in Rails - ruby-on-rails

Question

Everytime I start my Rails applications I get LoadError with the following output.
On Rails 2.3.8:
no such file to load -- sqlite3/sqlite3_native
<internal:lib/rubygems/custom_require>:29:in `require'
On Rails 3.0.0:
no such file to load -- bundler
<internal:lib/rubygems/custom_require>:29:in `require'
I run the applications in the production mode on a development machine using Nginx + Passenger.
What is the reason of this issue? How can I solve it?
Thanks.
Debian GNU/Linux 5.0.6;
Ruby 1.9.2;
Rubygems 1.3.7;
Ruby on Rails 2.3.8, 3.0.0;
Nginx 0.8.50;
Passenger 2.2.15;
sqlite3-ruby 1.3.1;
bundler 1.0.0.rc.6.
Updated
All of my gems is installed by the unprivileged user in the local directory /home/<usernam>/.gem. If it helps, here's the gem env output:
RubyGems Environment:
- RUBYGEMS VERSION: 1.3.7
- RUBY VERSION: 1.9.2 (2010-08-18 patchlevel 0) [i686-linux]
- INSTALLATION DIRECTORY: /home/<username>/.gem
- RUBY EXECUTABLE: /usr/local/bin/ruby
- EXECUTABLE DIRECTORY: /home/<username>/.gem/bin
- RUBYGEMS PLATFORMS:
- ruby
- x86-linux
- GEM PATHS:
- /home/<username>/.gem
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- "gem" => "--no-ri --no-rdoc"
- :gemhome => "/home/<username>/.gem"
- :gempath => ["/home/<username>/.gem"]
- REMOTE SOURCES:
- http://rubygems.org/
Updated
I tackled with the problem. Its source was that I defined a custom gem path. That is I added to the ~/.gemrc file the following lines:
:gemhome: /home/<username>/.gem
:gempaths:
- /home/<username>/.gem
Thus all of my gems was placed in the specified directory but not the default one. For some reason Rubygems coundn't find it there and rose an exception.
When I removed that lines from the file the default paths was set for Rubygems and after I installed all the required gems and loaded my Rails applications all began to work.
Once again, the bug conditions are:
Nginx + Passenger;
The gempath is set to /home/<unprivileged_user>/.gem in ~/.gemrc;
An init.d script is creaded and added to the boot sequence (update-rc.d nginx defaults);
System is rebooted, server is started atomaticlally;
http://localhost/my_rails_app;
LoadError; no such file to load -- <gem_name>; <internal:lib/rubygems/custom_require>:29:in `require'.
Why can't Rubygems find gems in the custom location but can find them in default? That's the question.

Answer 1

I too had this problem when using RVM - I must have specified a gemset or something and not made it project specific. At any rate, read this rvm guide if you want to know the basics of RVM and try to specify a new gemset for your current folder / project, install a new rails gem to that gemset, and then use that gemset. For example, to create a new gemset for rails version 2.3.8:
$ rvm gemset create rails238
$ rvm ruby-1.8.7#rails238
$ gem install rails -v 2.3.8
Then if all went according to plan type rvm gemset use [gemsetName], or do rvm gemset list to see a list of installed gemsets, and to see if rails is working fine try rails -v and you should see rails 2.3.8

Answer 2

Check your system to locate where your rubies and gems are installed ( you can do this by "which ruby" and "which gem"). Usually, they're installed in the same folder (/usr/bin or /usr/local). If they are in different locations, there might be load error. Just a suggestion.