WordPress MU

I have migrated from Wordpress 2.7.1 to µ 2.7.1. Posts worked out fine, but I am having troubles with the user migration. I copied the wp_users and wp_usermeta tables and ran the following SQL command:

ALTER TABLE wp_users ADD spam TINYINT NOT NULL ,
ADD deleted TINYINT NOT NULL ;

And renamed them to wp_1_users and wp_1_usermeta.

Now I can find all the users (about 70) in the Site Admin menu but their user roles have vanished, and when I try to assign them new ones, there are no roles available. Just an empty drop-down box.

Do you know what the problem is?

I'm having the same issue, any follow up?

The WPMU tables are still wp_users and wp_usermeta, not wp_1_users adn wp_1_usermeta. That's the problem.