That is strange, too. I didn't realize that when you login as the super admin, you use the user name you created when installing - but when logging in as a user, you have to use the email. So thanks for pointing that out... I am going to modify my login screens for my clients to say "login/email".
Also, with encryption, it was pretty easy for me to modify to use either SHA1 or MD5. Let me know if you need any help with it.