ActionView::TemplateError (frozen? is defined by ActiveRecord) on line

After upgrading a project from rails 1.2.6 to rails 2.1 I ran into a few troubles.

A few notes:
I got this error "ActionView::TemplateError (frozen? is defined by ActiveRecord) on line ..." and fixed it with a migration like this:

  def self.up
    rename_column :accounts, :frozen, :iced
  end
  
  def self.down
    rename_column :accounts, :iced, :frozen
  end

Moved to mislav-will-paginate gem (replacing the old plugin).
Installed new version of GeoKit plugin.
Removed resource_fu, easily_migrate and acts_as_comparable plugins as I think most of what they do is now built into rails.