class Series
include Mongoid::Document
field :started_on, :type => DateTime
scope :aggregatable, lambda

end

If I am using bson_ext, I get the infamous "keys must be strings or symbols" error. I have updated my Gem file to point to this github repo and it still persists. This exact same issue is why I gave up on mongomapper and switched to mongoid. Stack trace:

ruby-1.8.7-p249 > Series.aggregatable.execute.to_a
TypeError: keys must be strings or symbols
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/bson-1.0.3/lib/../lib/bson/bson_c.rb:24:in `serialize'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/bson-1.0.3/lib/../lib/bson/bson_c.rb:24:in `serialize'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:364:in `construct_query_message'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:346:in `send_initial_query'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:324:in `refill_via_get_more'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:319:in `num_remaining'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:92:in `has_next?'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/gems/mongo-1.0.3/lib/../lib/mongo/cursor.rb:205:in `to_a'
from /home/michael/.rvm/gems/ruby-1.8.7-p249/bundler/gems/mongoid-af80db8e53d021c0543aa7940052c21b79dfde86-master/lib/mongoid/cursor.rb:79:in `to_a'