Actually, that does not sound like the same problem at all, as your error message indicates that the problem is an inability to connect to the FTP server, not the MySQL server (and these are different things altogether).
In your case, you need to confirm the proper hostname to use (either your domain name or yourservername.dreamhost.com, if your domain is not yet reachable via the web), your FTP user name (almost certainly different that your web account control panel login, and the FTP password (again, almost certainly different than your web account control panel login).
If can't sort these out from memory, review your account welcome email, where this is sent to you. If the problem is a user/password confusion, review your User's settings in the "Users -> Manage Users" section of the panel (you can "edit" the user to change the password).
As a last resort, use the "Contact Support" section of the account control panel to ask the technical support folks for assistance.
--DreamHost Tech Support