rails 1.2 已经悄悄release了

http://rubyforge.org/frs/download.php/16553/actionmailer-1.3.1.gem
http://rubyforge.org/frs/download.php/16550/actionpack-1.13.1.gem
http://rubyforge.org/frs/download.php/16556/actionwebservice-1.2.1.gem
http://rubyforge.org/frs/download.php/16547/activerecord-1.15.1.gem
http://rubyforge.org/frs/download.php/16559/rails-1.2.1.gem
http://rubyforge.org/frs/download.php/16507/activesupport-1.4.0.gem

惨啊,我升级到rails1.2后(并将activerecord-1.14.4等文件夹删除)，出现下面的错误：

D:\RubyWorkspace\jxkh>mongrel_rails start -p88
** Starting Mongrel listening at 0.0.0.0:88
** Starting Rails with development environment ...
d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:196:in `activate': can't activate act
iverecord (= 1.15.1), already activated activerecord-1.14.4] (Gem::Exception)
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:32:in `re
quire'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:229:in `activate'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:228:in `each'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:228:in `activate'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:214:in `activate'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:213:in `each'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:213:in `activate'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:66:in `active_gem_with_o
ptions'

请问应该如何升级啊？难道代码都要重新做过？