Multi-DB Plugin : Database Error: Access denied for user 'wordpress_9'@'%' to da

I am attempting to install 'multi-db' plugin.
Setting up for 256 DB's, I access the following url for to test;

I get the following response only;

Houston, we have a problem!
Looks like you need to create your new db's! If you're lucky, this link still works - click me
Database Error: Access denied for user 'wordpress_9'@'%' to database 'wordpress_7c8'

Tested on PHP 5 & MySQL 5
Make sure all of your new db's exist (green text next to table name in db column below)
In the status section, each table should show not in new db (unless you've already run this script)
To start the copy process click here
Be patient, depending on how many blogs you have, this could take a while
Once completed, refresh this page by clicking here
Check to make sure that in the status section all tables say table in new db
Rejoice, I probably just saved you hours of your life!
If this didn't work, don't blame me. Sometimes life is just like that..
table name table info new db status