Hey daniel_not_dan,
This may be an issue with how you configured your new database. I would email your hosting provider and double check with them about the error. You will also want to pay attention to the methodology in which the database names and users names are created.
On some hosts you will create a database called 'mydatabase' but behind the scenes they create a database called 'yourdomain_mydatabase' so you have to connect with the correct parameters which would really be 'yourdomain_mydatabase'. This isn't true of all hosts, but some modify the names a bit. Your hosts documentation should have the full details for how to do this.
Hope this helps...
