Custom Rails Validation (Doesn't seem to be working)

I've got the following Model for Accounts

require 'net/http'require 'uri'require 'date'class Account < ActiveRecord::Basevalidates_presence_of :username, :password, :on => :updatevalidate :valid_expiry_date, :on => :update  def valid_expiry_date   reply = Net::HTTP.get URI.parse("http://api.rapidshare.com/cgi-bin/rsapi.cgi?sub=getaccountdetails_v1&type=prem&login=" + username +"&password=" + password)   account = Time.at(reply[80..90].to_i)   if (Time.now + 2419200) <= account     return true         else     return false     errors.add_to_base("Sorry this account isn't valid")    end endend

I know the code works in a ruby.rb file and will return true or false, however I seem to be having rather a lot of difficultly trying to translate this code into an actual validation, any help would be much appreciated. Thanks

Its also defiantly at least connecting to the website as my firewall asked me if the Terminal was allowed to access it.

At the moment not only is it displaying no errors it's actually letting anything through and saving it.