Update:
I forgot to mention that I installed wordpress at https://www.kochibeat.com/blog. I copied index.php to the root directory. I have not been able to modify permalinks, so I have no .htaccess file to move.
I just realized a mistake. I was forgetting /blog/ before wp-login.php. Now, I can see login at https://www.kochibeat.com/blog/wp-login.php. Afterwards, though, there are many warning messages similar to the one in the post above.
Thanks!