Unable to add a new user

Hi.
I am new here. So I am sure I am not doing something right.
I have two blogs: one in English and another one is a multi language (installed from a russian site). When I try to add new user in the multi langv. site , it works fine.
But in the English site, when i go to add a new user,
it promts me for an email only (not asking about names and so on) and then send an email to that individual sugestig for him/her to open a new account and create a blog.

Any ideas?

Thanks

z