Hello!
I have a same problem with login to my admin account.
The link to the site:
http://altarin.freehost.int.ru/
I checked, the registration is working fine, I can log in with registred account, but I can't log in with my admin account. Have no idea what to do.
I sort of solved problem.
I changed usergroup for my working test account, and it finally works.
But I don't understand why my fisrst account didn't worked :C