When I select an item, I don't see a way to add it to my cart anywhere. Are can you tell me a specific product I should be able to add?
Beyond that, all I can recommend is checking your JFBConnect -> Facebook settings and set the "Show login credentials in popup" setting to Yes. That may keep the user on the same page instead of going through a server redirection loop. If that doesn't work though, we'd have to test further.
Finally, it looks like you're on an older version of JFBConnect. The latest is v6.0.6, which has full support for the recent changes in Facebook's Graph API v2 update. It's possible there's some issues that the changes in that update will fix. For more information, see our
Facebook Graph API v2 and what it means for your site
blog post.
I hope that helps,
Alex