Exception using _forward() method

Hey .

I'm doing this: $this->_forward( "index",
"index", "default" ); into another
module named "login", but I got an exception when
I try to forward to the "default" module:

Fatal error:  Uncaught exception
'Zend_Controller_Dispatcher_Exception' with message 'Invalid
controller specified (error)' in
/usr/local/lib/zfw/ZendFramework-1.0.3/library/Zend/Controll
er/Dispatcher/Standard.php:198
Stack trace:
#0
/usr/local/lib/zfw/ZendFramework-1.0.3/library/Zend/Controll
er/Front.php(929):
Zend_Controller_Dispatcher_Standard->dispatch(Object(
Zend_Controller_Request_Http),
Object(Zend_Controller_Response_Http))
#1 /var/www/html/index.php(49):
Zend_Controller_Front->dispatch()
#2 
  thrown in
/usr/local/lib/zfw/ZendFramework-1.0.3/library/Zend/Controll
er/Dispatcher/Standard.php on line 198

Why I'cant forward ?

Thx for any help.