We had a report of another user with a similar issue during installation but have been unable to determine the cause. Can you provide us with super admin access to your site? You can Private Message us credentials by clicking the mail icon under our name to the left.
We've tested JFBConnect 8.0.4 on many different sites and have many users who have successfully installed it, but definitely want to get to the bottom of this as soon as possible to understand what may be wrong. If it's not possible to provide super admin access, please let us know any details you can about your site, like PHP, Apache and MySQL versions.
Thanks,
Alex