Rails - Aug 2005 - Finding rows in table a with zero related rows in table b, part ii

OK. After a little more digging in MySQL''s manual on SubSelects,
I''ve
changed the finder_sql entry in my model declaration:

class District < ActiveRecord::Base
	has_many 	:interviewers,
					:order => "lname, fname"
	has_many 	:applicants
	has_many 	:unassigned_applicants,
				:class_name => "Applicant",
				:finder_sql => "select a.* from applicants a left join 
applicants_interviewers ai " +
					"on a.id = ai.applicant_id where ai.applicant_id is null"
end

Running that SQL through the mysql command-line tool returns exactly the 
data I''m looking for. However, in my district_controller.rb file,
I''ve
got this method:

	def unassigned_list
		@dist = District.find( params[:dist_id] )
		@applicants = @dist.unassigned_applicants.find( :all )
		@sub_title = "Unassigned Applicants (" + @applicants.size.to_s +
")"
		render :template => "district/app_list"
	end

When I go to the page that calls this method, it throws back this error:

NoMethodError in District#unassigned_list
undefined method `expects_array?'' for #<Array:0x2271d04>

I have no idea what this is trying to tell me. What is the 
expects_array? method doing? Or trying to do?

-Brian