If you get the error:
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please
install the mysql gem and try again: gem install mysql.
Here’s what happened.
Windows, InstantRails & Rails 2.2+ will not work out of the box
gem install mysql will successfully install the gem but then silently fail if the gem cannot find MySQL. Because InstantRails is designed to install cleanly, it doesn’t modify your path and so gems cannot find the MySQL path. To fix this, go to Control Panel->System->Advanced System Settings->Environment Variables->Path and add C:InstantRailsmysqlbin & C:InstantRailsrubybin to the path. Restart everything that can be restarted and try again.
Windows, Ruby, MySQL 5.1 & Rails 2.2+ will not work out of the box.
Install MySQL 5.0 instead.
either of these should fix the problem.