There are a few bugs with zpBootstrap registration page.

1. the checkbox sais "Afficher le mot de passe" even though I have English language.
2. I translated it to find out what it means. But it does not do what it sais. Password you type are hidden no matter state.
3. It is impossible to register. I always end up with "Registration failed. Your passwords did not match.". Switching to standard theme, it works fine.

There is also a bug with login:

1. If trying to log in with wrong user/pass, I am sent back to home page, not to login page.

hi
please note that this theme has not been maintened since zenphoto 1.4.4.
but I agree with these 4 issues.

Ok, and zpmobile theme has problems with rating plugin. Which mobile friendly theme do you recommend?

Try the zpBase theme for example. All themes that are reponsive (unless we forgot to tag one correctly) you can view here: http://www.zenphoto.org/page/search/tags/responsive
We will have more official mobile friendly themes in the future for sure.

as far I have tested it, all issues of zpBoostrap 1.4.3 are fixed zpBoostrap 1.4.6