The problem of registering membership in the site

Problem when registering in membership.
Every time someone wants to register for one of my programs in membership
there are different error:
  1. an error that there is a problem with the name or password.
(I tried to register with a username and password
  which was exactly new.)
2. despite the error. creates okaunt in wordpress
- Without going to pay !!!
3. When you try to re-register, writes that such e-mail address already exists