Ok so we know everything is ok on the host side of things. Double check and recheck that mainfile.php, it's very important. It's the only thing it could be and nothing else.
No trailing slashes, and make sure everything is 'between the quotes'. Once again, double check spelling and check your SQL via the admin panel on your host to be sure of the proper user/pass.
Your file should look exactly as below with your own settings.
// XOOPS Physical Path
// Physical path to your main XOOPS directory WITHOUT trailing slash
define('XOOPS_ROOT_PATH', '
/path/to/your/root)';
// XOOPS Virtual Path (URL)
// Virtual path to your main XOOPS directory WITHOUT trailing slash
define('XOOPS_URL', '
http://www.yourdomain.com');
// Database
// Choose the database to be used
define('XOOPS_DB_TYPE', 'mysql');
// Table Prefix
// This prefix will be added to all new tables created to avoid name conflict in the database. If you are unsure, just use the default 'xoops'.
define('XOOPS_DB_PREFIX', 'xoops');
// Database Hostname
// Hostname of the database server. If you are unsure, 'localhost' works in most cases.
define('XOOPS_DB_HOST', 'localhost');
// Database Username
// Your database user account on the host
define('XOOPS_DB_USER', '
your_DB_userName');
// Database Password
// Password for your database user account
define('XOOPS_DB_PASS', '
yourPassword');
// Database Name
// The name of database on the host. The installer will attempt to create the database if not exist
define('XOOPS_DB_NAME', '
your_DB_name');
