When trying to activate this plugin (version 1.3.4) I get the following error (amended to remove reference to my home directory):
Mailing list: An error occured during activation
this case1
Plugin could not be activated because it triggered a fatal error.
Fatal error: Cannot redeclare zing_mailz_notices() (previously declared in {my home}/wp-content/plugins/mailz/mailz.php:78) in {my home}/wp-content/plugins/mailz/mailz.php on line 104