A significant number of Rails developers have reported problems installing gems with the updated RubyGems release. If you’re experiencing a problem that looks anything like this:

$ gem update sqlite3-ruby Updating installed gems… ERROR: While executing gem … (NoMethodError) undefined method `refresh’ for #<hash:0x14e0a4c>

…you should remove your local source_cache file. This is the file that locally caches any gem metadata from the gem server to avoid having to re-download it every time you execute a gem command.

To discover the location of this file on your system, run the following command:

$ gem env RubyGems Environment:

• VERSION: 0.9.2 (0.9.2)
• INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8
• GEM PATH:
• /usr/local/lib/ruby/gems/1.8
• REMOTE SOURCES:
• http://gems.rubyforge.org

The source_cache file should be in the path labeled by GEM PATH. Removing that file should clear up any related issues.

This solution is a workaround pending a fix by the RubyGems team.