Rails Ruby on Rails

Whenever I try running any database related rake task "db:create", I got this error "rake aborted! uninitialized constant Mysql::Error"

from 'databases.rake' line 64

error_class = config['adapter'] =~ /mysql2/ ? Mysql2::Error : Mysql::Error

when I commented that line out everything worked just fine.

the database got created, migrations worked fine and all.

I used NetBeans 6.9.1 in windows7
the db gems were:
jdbc-mysql, activerecord-jdbc-adapter, activerecord-jdbcmysql-adapter

database.yml

development:
  adapter: jdbcmysql
  encoding: utf8
  reconnect: false
  database: myapp_development
  pool: 5
  username: root
  password: 12345
  host: localhost

...