Programmers who work mostly on windows have seen this kind of errors many times.. as a windows programmer I have been through many sites and collect d relevant data, now I am showing it to you..

The errors which might come to you something like this:
no such file to load mysql
rake aborted: no such file to load mysql
The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql
Could not find RubyGem rake-compiler (~> 0.5)

To solve such problems follow these steps:
Step 1. Update rubygems to the latest version(like I upgraded it to 1.3.5).
Step 2: install rake-compiler(by gem install rake-compiler).
Step 3: if already installed hoe gem update it(gem update hoe) or install a fresh one.
Step 4: Download libMySQL.dll from here and copy it into C:/ruby/bin or wherever your ruby is installed, but make sure it should be in bin directory.
Step 5: Stop the mysql service, from Control Panel -> Administrative tools -> services -> mysql, and then restart it.

That’s it. You are done, after all these steps you can try
rake db:migrate
Suppose if that doesn’t work then after 4th step, stop the mysql service and restart your system.

I welcome all of you to post your comments, feedbacks, queries

Cheers!!
Puneet Pandey