Instructions for Multi DB usage page says blogs.php file needs to be changed:
$dbname = "old_db_name"; //This is your current database
Is this the main db for the wp installation?
$blog_table_prefix = 'wp_'; //Prefix of your wpmu blog tables, most likely this won't need to be changed
This is clear..
$newdb_prefix = 'newdbname'; //This is the prefix of the db's you're moving your tables into - we assume they are all the same, if not, you're in trouble
Here you say prefix but seem to be asking for a db name? Please clarify.