Problem with ActionMailer/SMTP

hi, i’m trying to make the user account confirmation work in my site,
but i couldn’t fix this error,

Processing UsersController#create (for 189.85.180.50 at 2009-09-23
16:44:30) [POST]
Parameters: {“commit”=>“Criar novo usuário”,
“authenticity_token”=>“UX+z7gZGHLo5+1LkW0duFvu69YiHC7H0baMY/Sbtyi8=”,
“user”=>{“password_confirmation”=>“paulogeyer”,
“password”=>“paulogeyer”, “login”=>“paulo”,
“email”=>“[email protected]”}}
Sent mail to [email protected]

ArgumentError (wrong number of arguments (3 for 2)):
/usr/lib/ruby/1.8/net/smtp.rb:525:in start' app/models/user_observer.rb:3:in after_create’
/usr/lib/ruby/1.8/observer.rb:185:in notify_observers' /usr/lib/ruby/1.8/observer.rb:184:in each’
/usr/lib/ruby/1.8/observer.rb:184:in notify_observers' app/controllers/users_controller.rb:19:in create’
/usr/lib/ruby/1.8/phusion_passenger/rack/request_handler.rb:95:in
process_request' /usr/lib/ruby/1.8/phusion_passenger/abstract_request_handler.rb: 207:in main_loop’
/usr/lib/ruby/1.8/phusion_passenger/railz/application_spawner.rb:
378:in start_request_handler' /usr/lib/ruby/1.8/phusion_passenger/railz/application_spawner.rb: 181:in spawn_application!’
/usr/lib/ruby/1.8/phusion_passenger/utils.rb:183:in safe_fork' /usr/lib/ruby/1.8/phusion_passenger/railz/application_spawner.rb: 153:in spawn_application!’
/usr/lib/ruby/1.8/phusion_passenger/spawn_manager.rb:272:in
spawn_rails_application' /usr/lib/ruby/1.8/phusion_passenger/abstract_server_collection.rb: 80:in synchronize’
/usr/lib/ruby/1.8/phusion_passenger/abstract_server_collection.rb:
79:in synchronize' /usr/lib/ruby/1.8/phusion_passenger/spawn_manager.rb:255:in spawn_rails_application’
/usr/lib/ruby/1.8/phusion_passenger/spawn_manager.rb:154:in
spawn_application' /usr/lib/ruby/1.8/phusion_passenger/spawn_manager.rb:287:in handle_spawn_application’
/usr/lib/ruby/1.8/phusion_passenger/abstract_server.rb:352:in
__send__' /usr/lib/ruby/1.8/phusion_passenger/abstract_server.rb:352:in main_loop’
/usr/lib/ruby/1.8/phusion_passenger/abstract_server.rb:196:in
`start_synchronously’
/usr/lib/phusion_passenger/passenger-spawn-server:61

Rendering /var/www/100empresas/public/500.html (500 Internal Server
Error)

here follows the code

user_observer.rb line #3

2: def after_create(user)
3: UserMailer.deliver_signup_notification(user)
4: end

users_controllers line #19

18: @user = User.new(params[:user])
19: @user.register! if @user && @user.valid?
20: success = @user && @user.valid?

and my email configuration from environment.rb

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
:address => “smtp.gmail.com”,
:port => 587,
:authentication => :plain,
:domain => “empreendedor.com.br”,
:user_name => “@empreendedor.com.br",
:password => "

}

any ideas? It is quite obscure to me