Hi,
Today I installed this Module from most current download (v3.3 last updated 3 Sep 2014)
I'm currently using Zen Cart Version v1.5.1.
Though we have a multitude of other contributions installed i cannot see any cross over issues.

After installation (option 2 with Master Password) I am unable to log into Admin, after entering user and pass the page redirects back to
MYSITE.COM/ADMIN/login.php.
log shows
PHP Fatal error: Class 'zcPassword' not found in /home/sites/MYSITE.COM/public_html/includes/functions/password_funcs.php on line 18

If i revert back to original version of /includes/functions/password_funcs.php i can log into admin,
then if i change to the updated version of /includes/functions/password_funcs.php whist logged in this module will function as expected.
Has anyone else seen this behaviour?
I'm assuming there is a change to be made in the password_funcs.php file but can't seem to zone in on it??