can't use db:seed in rails

I updated my rails gem to 2.3.5 but I keep getting this error when running db:seed:

$ rake db:seed --trace
(in c:/Documents and Settings/Owner/workspace/thepatstudio)
rake aborted!
Don't know how to build task 'db:seed'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1728:in `[]'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2050:in `invoke_task'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
c:/Ruby/li开发者_运维技巧b/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31
c:/Ruby/bin/rake:19:in `load'
c:/Ruby/bin/rake:19

~/workspace/thepatstudio (master)
    $ rails --version
    Rails 2.3.5

My environment.rb has the correct rails version on it and I also ran rake rails:update. What can I do?

Have you launch the rake task to update your environment after update your gem ?

rake rails:update