I am sorry that you have troube installing it. Many users have no issues at all. But sadly not all servers are setup exactly the same so it always might be not working everywhere. We of course can't test on every possible configuration.
Regarding the email, for that one of the mailer plugins must be enabled and your server must be setup to be able to sent mails at all. There an email address must be defined Zenphoto should sent from. You might need to contact your host about that.
If we should be able to help any further please also let us know some details about your server (PHP, MySQL version and such)
Regarding passwords please also try this: http://www.zenphoto.org/2009/03/troubleshooting-zenphoto/#16