Fatal error: Call to a member function render()

I didn't see that error when following those instructions. I was a guest user and not logged in. Do you only see this issue when logged into your site or do you always see it? If you see it when a guest, can you clear your browser cache and try again to see if that works? That will help understand if there's some cookie stuck that may be causing it.

As for other things:
* The only 'widgets' I see on that page (which calls that render function) is the social sharing buttons in the bottom left of the page. Is that all you know of on that page?
* If you have caching enabled, try disabling it to see if that fixes the problem.
* JFBConnect v6.0.6 is available. It's definitely worth a shot upgrading as there are many fixes in the 5 minor releases between 6.0.1 and 6.0.6. I don't recall any being specifically for what you mention, but it shouldn't hurt.

Finally, on an unrelated note, I really like your Login slideout area. We're hoping to add a style like that later this year. The titles for "Connect to get started." are too similar to the background color and hard to read, just so you know.

I hope the above helps, but keep us posted on what you find!
Alex