Go to JIG settings > Facebook tab > Facebook overview slug setting and click the link in the help bubble to flush rewrite rules. If you've customized the slug, revert it to facebook-album as you may have set a conflicting slug.
If it didn't help: certain plugins interfere with rewrite rules. Try disabling some that you think have the capability to add a custom URL "endpoint" to your site. I found that the "Ultimate Taxonomy Manager" is one of those. Use WCK instead. The JIG rewrite rules (endpoints) are added by add_rewrite_endpoint function and should work just about anywhere on your site.