Cannot create a user with an empty login name

[admin]

I have a wordpress site

mysite.com

and a subdomain

mysite.com/subdomain

. I need to copy users from

mysite.com/subdomain

to

mysite.com

. I tried

INSERT INTO wp_users (<fields>) SELECT <fields> FROM subdomain_users

wp_users fields are

user_login

,

user_email

and

user_registered

and then let them all to reset their password.

everything works fine but there are two problems:

<ul>
<li>when the administrator wants to edit users profile or users want to edit their profile face this error:

Cannot create a user with an empty login name.

</li>
<li>the text and visual tab in wp tinymce editor are hidden for these users when adding posts. but if I add new user as usual users>>Add new then they can see the visual and text tabs.</li>
</ul>

Any advice and suggestion will be appreciated.