I've picked about a dozen extensions (all are in the customization database and have been validated) to add to the beta forum. The ones that are added without a problem are: Auto Database Backup, Browse Happy, Database Optimize & Repair Tool, Error pages, Google Analytics, Password Strength and Scroll to Top.
The ones that I can't add are: About us, Board Announcements, Board Rules, Pages and Precise Similar Topics. They each give me an error message when I click the 'Enable' button on the confirmation page. That error is:
I've recently learned my way around phpBB a little bit, but I'm at a complete loss as to what to do here.Something went wrong during the request and an exception was thrown. The changes made before the error occurred were reversed to the best of our abilities, but you should check the board for errors.
A required module does not exist: ACP_CAT_DOT_MODS