Users Can't Log-in

My site users are unable to log-in :: Login Failed! You entered an invalid username or password.

and they are also unable to log-in through http://www.mydomain.com/wp-admin :: ERROR: Your account is still pending approval.

But the accounts are all double opt-in activated as well as administrator activated!

I already saw this thread but it doesn’t answer my problem.

http://wordpress.org/extend/plugins/wp-members/