After two months, I have started working on rails again and upgraded Rails to 2.3.2 on my laptop. After upgraded when I have tried to run a sample rails application and got following errors:
=> Booting WEBrick
=> Rails 2.3.2 application starting on http://0.0.0.0:3000
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql.
=> Call with -d to detach
[2010-03-21 04:39:09] INFO WEBrick 1.3.1
[2010-03-21 04:39:09] INFO ruby 1.8.6 (2007-09-24) [i386-mswin32]
[2010-03-21 04:39:09] INFO WEBrick::HTTPServer#start: pid=5032 port=3000
=> Ctrl-C to shutdown server
After getting the above error I have installed newer version of mysql gem but problem was not solved. Then just copy the MySQL dll from mysql/bin/libmysql.dll to ruby/bin/libmysql.dll. And it worked perfectly.