Upgrading vb 5 To Latest Version

[vbSuperfan]

I'm posting this in this old thread since Google refers to it when googling the "Cannot declare class vB_dB_Assertor" error message.

This problem just happened to me too (on a local XAMPP install on Windows, with PHP 7.3.8 and MariaDB 10.4.6), and the solution above worked for me, i.e. to change:

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

to:

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

in the /core/includes/config.php file.

For some strange reason, the installer's first stage fails to fill in this value, which in turn cause this critical problem. Very strange?!