Major Problem

[Grinderhand]

$config['Database']['dbtype'] = 'mysqli';

Unless you're sure you have this type of database, try changing this line to 'mysql'

$config['SpecialUsers']['undeletableusers'] = 'xilo,gurugeak,[GH]SpâdÈz';

Replace the user names on this line with their user numbers, as can be found in AdminCP -> Users -> Search for User. When you are presented with the users info, their user number will be right at the top.

$config['Mysqli']['ini_file'] = '';

If you're sure you have a MySQLi type database, you may have to put the location of the .ini configuration file between the ' 's. But before you mess with this, try changing to MySQL database type first and see if that helps.