vBulletin 4.1 Database user authentication issue

I have an issue where I am unable to complete the vBulletin 4.1 install.

[quote]Due to the following errors, the install/upgrade can not continue:

Database connection failed due to unexpected error:
(1044) Access denied for user ‘username_sql’@‘’ to database ‘database_db’[/quote]

I have checked that the username and password, host and port are all correct in config.php and confirmed it. I am also able to log in via phpMyAdmin with those credentials. The actual username and db name renamed here for security purposes as normal.

Any thoughts?

EDIT: I have also checked the database user through the web panel, it has all rights to the DB (Select, Insert, Update, Delete, Create, Drop, Index, Alter) and the allowable hosts is %.dreamhost.com as normal.