Thank you for the reply. Unfortunately, my explanation was not clear. Apologies.
There are Wordpress files present in the /var/www/domain_name directory, but they were installed via a separate process (thus, the error messages). My question is as follows: is it possible to either edit or remove TINYCP Application Installer files so that the built-in Wordpress installer script is removed entirely?
Error messages gone after v463 upgrade. I'll settle for that. Thank you (and kudos again for the best control panel in its category).
Try the developer's suggestion and uninstall from the command line:
(In my case, I started from scratch and had my VPS host reinstall Ubuntu (18.04.2 LTS)).