I need help getting alert emails to work

I now have this alert.

$config['alerts']['alerter']['default']['descr']   = "Default Email Alert";

$config['alerts']['alerter']['default']['type']    = "email";

$config['alerts']['alerter']['default']['contact'] = "tr@zitcom.dk";

$config['alerts']['alerter']['default']['enable']  = TRUE;

But not alerts J

Whats my problem?

Thomas