Typo site somewhat hosed, need tips to recover

My typo site had not been updated in a while, but the host it runs on
has undergone upgrades recently. Some time over the past month or
two, suddenly I couldn’t access vital admin areas (to write a post,
review/confirm feedback, etc.) Being somewhat impatient, without
investigating the cause of the errors, I upgraded in-place using svn
update and rake db:migrate. Things seemed to go well. The blog
itself looks fine, but I still can’t access the same parts of the
admin interface.

Here’s a sample error after upgrading. How do I proceed from here to
get my blog functioning properly again?

Processing ContentController#new (for 71.7.237.23 at 2008-08-01
09:14:07) [GET]
Session ID: 001b43dc4ab82bfc495e757edeed72d3
Parameters: {“action”=>“new”, “controller”=>“admin/content”}

NoMethodError (undefined method []' for #<Enumerable::Enumerator:0x7f0bd90cb340>): /vendor/rails/activerecord/lib/../../activesupport/lib/active_support/core_ext/string/access.rb:53:inlast’
/lib/stateful.rb:21:in method_missing' (__DELEGATION__):2:insend
(DELEGATION):2:in published?' /app/models/article.rb:301:inallow_comments=’
/vendor/rails/activerecord/lib/…/…/activesupport/lib/active_support/core_ext/object/misc.rb:28:in
returning' /app/models/article.rb:299:inallow_comments=’
/app/controllers/admin/content_controller.rb:214:in
get_or_build_article' /vendor/rails/activerecord/lib/../../activesupport/lib/active_support/core_ext/object/misc.rb:28:inreturning’
/app/controllers/admin/content_controller.rb:213:in
get_or_build_article' /app/controllers/admin/content_controller.rb:145:innew_or_edit’
/app/controllers/admin/content_controller.rb:55:in new' /vendor/rails/actionpack/lib/action_controller/base.rb:1159:insend’
/vendor/rails/actionpack/lib/action_controller/base.rb:1159:in
perform_action_without_filters' /vendor/rails/actionpack/lib/action_controller/filters.rb:699:incall_filters’
/vendor/rails/actionpack/lib/action_controller/filters.rb:727:in
run_before_filters' /vendor/rails/actionpack/lib/action_controller/filters.rb:666:incall’
/vendor/rails/actionpack/lib/action_controller/filters.rb:666:in
proxy_before_and_after_filter' /vendor/rails/actionpack/lib/action_controller/filters.rb:483:incall’
/vendor/rails/actionpack/lib/action_controller/filters.rb:483:in
call' /vendor/rails/actionpack/lib/action_controller/filters.rb:724:inrun_before_filters’
/vendor/rails/actionpack/lib/action_controller/filters.rb:697:in
call_filters' /vendor/rails/actionpack/lib/action_controller/filters.rb:691:inperform_action_without_benchmark’
/vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:inmeasure’
/vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue' /vendor/rails/actionpack/lib/action_controller/rescue.rb:199:inperform_action_without_caching’
/vendor/rails/actionpack/lib/action_controller/caching.rb:678:in
perform_action' /vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:33:incache’
/vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in
cache' /vendor/rails/actionpack/lib/action_controller/caching.rb:677:inperform_action’
/vendor/rails/actionpack/lib/action_controller/base.rb:524:in send' /vendor/rails/actionpack/lib/action_controller/base.rb:524:inprocess_without_filters’
/vendor/rails/actionpack/lib/action_controller/filters.rb:687:in
process_without_session_management_support' /vendor/rails/actionpack/lib/action_controller/session_management.rb:123:inprocess’
/vendor/rails/actionpack/lib/action_controller/base.rb:388:in
process' /vendor/rails/actionpack/lib/action_controller/dispatcher.rb:171:inhandle_request’
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:115:in
dispatch' /vendor/rails/actionpack/lib/action_controller/dispatcher.rb:126:indispatch_cgi’
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:9:in
dispatch' /vendor/rails/railties/lib/fcgi_handler.rb:101:inprocess_request’
/vendor/rails/railties/lib/fcgi_handler.rb:149:in
with_signal_handler' /vendor/rails/railties/lib/fcgi_handler.rb:99:inprocess_request’
/vendor/rails/railties/lib/fcgi_handler.rb:77:in
process_each_request' /usr/lib/ruby/1.8/fcgi.rb:612:ineach_cgi’
/usr/lib/ruby/1.8/fcgi.rb:609:in each' /usr/lib/ruby/1.8/fcgi.rb:609:ineach_cgi’
/vendor/rails/railties/lib/fcgi_handler.rb:76:in
process_each_request' /vendor/rails/railties/lib/fcgi_handler.rb:50:inprocess!’
/vendor/rails/railties/lib/fcgi_handler.rb:24:in `process!’
/public/dispatch.fcgi:24

Rendering /var/www/vir/syn.theti.ca/typo/public/500.html (500 Internal
Server Error)

Thanks,
Ben

sprewell helped me fix this on irc. A downgrade of Ruby from 1.8.7 to
1.8.6 fixed it.

Thanks!
Ben