Apologies that this messageboard has been down for a few days. The pesky hosting company changed the database type from "mysql" to "mysqli" without telling me!
The web hosting company also moved from PHP5.5 to PHP7.0, and this version of MyBB doesn't work with 7.0
I managed to move it back to 5.5, but only until Jan.
I gotta upgrade MyBB.
I've now updated this board to the latest version of MyBB, and moved back to PHP 7.0