DB Host Error

When I try to install i get this error:

“This either means that the username and password information in your wp-config.php file is incorrect or we can’t contact the database server at localhost. This could mean your host’s database server is down.

Are you sure you have the correct username and password?
Are you sure that you have typed the correct hostname?
Are you sure that the database server is running? “

I am positive everything but the db host name is correct. Local host doesnt work so after consultation with my host she gave me the hostname as vicki-wp@dainty-tears.net I tried this but it also doesnt work. Any ideas?