I recently fixed a UBB.threads installation that had a crashed ubbt_TOPIC_VIEWS table. After some investigation, I discovered that the issue stemmed from the fact that this table, as well as ubbt_ONLINE, had been switched to the old MyISAM storage engine (as suggested in this thread).
InnoDB has long since replaced MyISAM as the default storage engine. I am unsure why MyISAM is recommended in this thread. It is no longer even in active development.
See
https://blogs.oracle.com/mysql/still-using-myisam-it-is-time-to-switch-to-innodb
