Graticule / acts_as_geocodable error?

Has anyone encountered this error using Graticule & acts_as_geocodable?

ActiveRecord::UnknownAttributeError (unknown attribute: precision):   (__DELEGATION__):2:in `__send__'   (__DELEGATION__):2:in `with_scope'   app/models/listing.rb:113:in `advanced_find'   ...

Here is line 113 in listing.rb:

  published.find(:all,     :origin => zip_code,     :within => miles,     :conditions => [conditions.join(" AND "), args, args],     :page => {:size => 10, :current => (page || '')},     :order => 'distance ASC')

The only mention of 'precision' is in my schema:

    t.decimal "latitude", :precision => 15, :scale => 12     t.decimal "longitude", :precision => 15, :scale => 12

and when I render the distance coming back:

  Distance: <b><%= number_with_precision listing.distance,     :precision => 1 %> miles away</b>

I can't figure out what "attribute" it's talking about. Thanks for the help.