nordlicht2016 on "[Plugin: Duplicator] Backup and restore works, but server gives PHP error msg"

Hi,
I was able to successfully backup WP, and also restore without any errors.
However when trying to access Wordpress, I get the message "Your PHP installation dos not seem to have the required mySQL extension".
This is really strange, because I already have a Wordpress installation running smoothly on the same server!
The only difference I can think of is that the working Wordpress installation is WP version 4.4.2, while the one I am trying to restore is 3.4.2.

Any advice what could be going on here?

Thanks,
Alex

https://wordpress.org/plugins/duplicator/