undefined method `close' for #<Paperclip::UploadedFileAdapter>

[squiter]

I get this error when I tried to upload a file in Active Admin. I'm using ruby 1.9.3, Rails 3.2.5 and paperclip 3.0.4.

My model:

class FinanceData < ActiveRecord::Base

  attr_accessible :title, :data, :data_file_name, :data_content_type, :data_file_size, :data_updated_at

  has_attached_file :data,
                    :path => "/public_html/testes/finance_data/:id/:style/:basename.:extension",
                    :url => "http://www.domain.com/testes/finance_data/:id/:style/:basename.:extension",
                    :storage => :ftp,
                    :ftp_credentials => Rails.root.join('config', 'paperclipftp.yaml')

end