Multi-DB - back-end login problems

Hi Guys,

I have some problems after setting up the multi-db plugin.
I've followed the steps from the plugin page.
Everything went fine - I was able to create the databases, assign permissions to user, updating the move-blogs.php & db-config.php and copying the tables from the main DB to the 256 databases created.
I even checked all the databases and all the tables are there.
Everything looks fine, but when I'm trying to login to the back-end, I can't.
I've tried to reset my pass but I've got the error: the user or email doesn't exists the.
The front-end is very slow and with a lot of css issues.

Currently I renamed the 2 files from wp-content (db_bk.php & db-config_bk.php) to be able to access the website and grant you the support permissions.

Could you please help me with this problem?