NameError: undefined method for class

[jritzi]

I recently upgraded a Rails 1.x app to 2.3, and along the way replaced the old sentry plugin with the latest gem. Now I run into the following error:

NameError: undefined method `credit_card_number' for class `Account'
from /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activesupport-2.3.10/lib/active_support/core_ext/module/aliasing.rb:33:in `alias_method'
from /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activesupport-2.3.10/lib/active_support/core_ext/module/aliasing.rb:33:in `alias_method_chain'
from /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/sentry-0.5.3/lib/active_record/sentry.rb:45:in `asymmetrically_encrypts'
from /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/sentry-0.5.3/lib/active_record/sentry.rb:14:in `generates_crypted'
from app/models/account.rb:3
from /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activesupport-2.3.10/lib/active_support/dependencies.rb:406:in `load_without_new_constant_marking'
...

Any idea what's going on here?