Is your database genealogia.gen.brionews.net ? Or do you mean the hostname is genealogia.gen.brionews.net?
The error message is saying that the hostname genealogia.gen.brionews.net does not exist although I can see from a whois that it does exist.
You can also get a MySQL error message like that when the database/username/password items are incorrect in some combination.
What I would suggest is to create another test sub-domain for your domain and then try another one-click install to the new sub-domain.
In the one-click install page you can select an already existing MySQL hostname such as genealogia.gen.brionews.net but create a new database of just a few letters/numbers such as abcd1234 (do not use full-stops).
Choose to create a new MySQL user and password and let the one-click install.
See how that goes after you have received the install email and configured PhpGedView.
If that works okay then you can delete the original one-click install from the one-click install and try again.
Sometimes a one-click can throw a wobbly and not install correctly so a re-install may work.
Opinions are my own views, not DreamHosts'.
I am NOT a DreamHost employee OK!! :@
You act on my advice at your own risk!