Help with migration issue

When attempting a migration I receive the following error:

uninitialized constant Rails::Plugin::Dependencies
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:131:in `const_missing'

Specifically, I want to update a Redmine (http://www.redmine.org)
instance from 0.8.0 to 1.2.1. The Redmine site has directions for
updating (http://www.redmine.org/projects/redmine/wiki/
RedmineUpgrade), which I've gotten to work up until the final
migration step. From the guide:

If you are upgrading from Redmine 0.8.x as part of this migration, you
need to upgrade the plugin migrations first:

rake db:migrate:upgrade_plugin_migrations RAILS_ENV=production

rake db:migrate_plugins RAILS_ENV=production

When I try to upgrade the migrations plugin, I get the following:

$ sudo rake --trace db:migrate:upgrade_plugin_migrations
RAILS_ENV=production
(in /var/www/html/redmine-1.2.1)
** Invoke db:migrate:upgrade_plugin_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
uninitialized constant Rails::Plugin::Dependencies
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:131:in `const_missing'
/var/www/html/redmine-1.2.1/vendor/plugins/redmine_google_calendar/
init.rb:47:in `reloadable!'
/var/www/html/redmine-1.2.1/vendor/plugins/redmine_google_calendar/
init.rb:47:in `each'
/var/www/html/redmine-1.2.1/vendor/plugins/redmine_google_calendar/
init.rb:47:in `reloadable!'
/var/www/html/redmine-1.2.1/vendor/plugins/redmine_google_calendar/
init.rb:51:in `evaluate_init_rb'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin.rb:
158:in `evaluate_init_rb'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin.rb:
154:in `evaluate_init_rb'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin.rb:
48:in `load'
/var/www/html/redmine-1.2.1/config/../vendor/plugins/engines/lib/
engines/plugin.rb:44:in `load'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin/
loader.rb:38:in `load_plugins'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin/
loader.rb:37:in `each'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/plugin/
loader.rb:37:in `load_plugins'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/initializer.rb:
369:in `load_plugins'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/initializer.rb:
165:in `process'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/initializer.rb:
113:in `send'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/initializer.rb:
113:in `run'
/var/www/html/redmine-1.2.1/config/environment.rb:20
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_original_require'
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`require'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:182:in `require'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:547:in `new_constants_in'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:182:in `require'
/usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/tasks/misc.rake:4
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:636:in
`call'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:636:in
`execute'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:631:in
`each'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:631:in
`execute'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:597:in
`invoke_with_call_chain'
/usr/local/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:590:in
`invoke_with_call_chain'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:607:in
`invoke_prerequisites'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:604:in
`each'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:604:in
`invoke_prerequisites'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:596:in
`invoke_with_call_chain'
/usr/local/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:590:in
`invoke_with_call_chain'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:583:in
`invoke'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in
`invoke_task'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`top_level'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`each'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`top_level'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in
`standard_exception_handling'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in
`top_level'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in
`run'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in
`standard_exception_handling'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in
`run'
/home/selfsimilar/.gem/ruby/1.8/gems/rake-0.8.7/bin/rake:31
/usr/local/bin/rake:19:in `load'
/usr/local/bin/rake:19

script/about fails, too right now.
$ RAILS_ENV=production script/about
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/dependencies.rb:131:in `const_missing': uninitialized
constant Rails::Plugin::Dependencies (NameError)
    from /var/www/html/redmine-1.2.1/vendor/plugins/
redmine_google_calendar/init.rb:47:in `reloadable!'
    from /var/www/html/redmine-1.2.1/vendor/plugins/
redmine_google_calendar/init.rb:47:in `each'
    from /var/www/html/redmine-1.2.1/vendor/plugins/
redmine_google_calendar/init.rb:47:in `reloadable!'
    from /var/www/html/redmine-1.2.1/vendor/plugins/
redmine_google_calendar/init.rb:51:in `evaluate_init_rb'
    from /usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/
plugin.rb:158:in `evaluate_init_rb'
    from /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.11/lib/
active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
    from /usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/
plugin.rb:154:in `evaluate_init_rb'
    from /usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/rails/
plugin.rb:48:in `load'
     ... 11 levels...
    from /usr/local/lib/ruby/gems/1.8/gems/rails-2.3.11/lib/commands/
about.rb:1
    from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
31:in `gem_original_require'
    from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
31:in `require'
    from script/about:4

Redmine 1.2.1 recommends some fairly specific requirements(http://
www.redmine.org/projects/redmine/wiki/RedmineInstall#Requirements),
which I believe I've matched:
$ ruby -v
ruby 1.8.6 (2008-08-11 patchlevel 287) [i686-linux]
$ gem list --local

*** LOCAL GEMS ***

actionmailer (2.3.11)
actionpack (2.3.11)
activerecord (2.3.11)
activeresource (2.3.11)
activesupport (2.3.11)
arrayfields (4.7.0)
fastthread (1.0.1)
fattr (1.0.3)
git-rails (0.2.1)
hoe (1.8.3)
i18n (0.4.2)
main (2.8.3)
passenger (2.0.6)
rack (1.1.1)
rails (2.3.11)
rake (0.8.7)
rubyforge (1.0.2)
rubygems-update (1.5.0)
tzinfo (0.3.12)

$ gem -v
1.3.7

My best guess at this point is that one of the gems or gem itself is
not quite on the right version. The requirements page has a
compatibility note:
RubyGems 1.3.7 or higher is required with following limitations :
    Rails 2.3.5 will fail with RubyGems 1.5.0 or later, stick to
previous versions of RubyGems !
    Rails 2.3.11 will fail with RubyGems 1.7.0 or later, stick to
previous versions of RubyGems !

I'm running 1.3.7, which should work, but it's the minimum version. I
could try to update to 1.7.0, but I'd need to update Ruby core as
well, I'm pretty sure.

I don't have much experience with RoR, so I may have missed something
obvious. Any help would be greatly appreciated.

Thanks