alcero I notice the same blank page error as default ( https://support.alcero.com/?lang=en_US does work though), but even after installing the French language pack in my system I'm unable to replicate the issue - it all works for me. Could the language file maybe have been corrupted during upload? If you go to Admin -> Dashboard -> Information do you see the language pack listed as below?

(You most likely won't have the en_GB one, but I like my u's still present in words 😆 ) You can skip the "for version 1.10" part, as that's the latest language pack there (currently) is from the download page.
EDIT: on the same information page, do you have any PHP extensions with a cross next to them?