Configuring and running Ruby-On-Rails migrations

I'm (completely) new to ROR and have got an application to maintain and upgrade. I've the source code and am trying to build database using db:migrate rake command. I've started using Aptana Studio for the development. When I run dg:migrate I get following errors:

rake db:migrate
(in G:/Projects/.../.../trunk)
MissingSourceFile no such file to load -- rcov/rcovtask
WARNING: rcov tests won't work
Looking for release_type overrides ...
=> Loading G:/Projects/.../.../trunk/config/release_type_config.rb
DEPRECATION WARNING: ActiveRecord::Base.allow_concurrency=has been deprecated and
no longer has any effect. Please remove all references to allow_concurrency=.. 
(called from allow_concurrency= at D:/Ruby/lib/ruby/gems/1.8/gems/
activerecord-2.3.5/lib/active_record/connection_adapters/abstract/
connection_specification.rb:开发者_开发技巧98)
DEPRECATION WARNING: ActiveRecord::Base.verification_timeout= has been deprecated
and no longer has any effect. Please remove all references to 
verification_timeout=.. (called from verification_timeout= at    
D:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/
connection_adapters/abstract/connection_specification.rb:108)
rake aborted!
no such file to load -- hpricot

I've installed hpricot gem also (version 0.8).

What is the remedy for this?

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Install the rcov gem:

gem install relevance-rcov --source http://gems.github.com

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The most significand error is

rake aborted!
no such file to load -- hpricot

You need hpricot. You can install it running the following command on the command line

gem install hpricot

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Maybe your system can't find the gems. This could be a path problem, see this post for details.