Thanks for the update. All is OK now.
Just so people in the WordPress.org forums can see your reply:
“Double check that the red URL the plugin indicates on the settings page is exactly the same as the Facebook Website > Site URL and that the Facebook App Domain field is empty. Note that you have to click on ‘Website’ to ‘open’ this field.”
The second line of my first post stated that the URL is identical, having been directly copied and pasted from the ALTF Settings page.
And in both cases, the Domain field is empty.
You posted the wrong link, but thanks for updating. http://lesterchan.net/wordpress/readme/wp-dbmanager.html
I might suggest waiting to post an update until the changelog can be updated. I appreciate your hard work, though.