[Plugin: Social Access Control] Lose access to Admin panel when Social Access is activated

I am just beginning to put together a WP blog and I very much wanted to use Social Access Control and the other plugins of Social Privacy.

Anyway I installed the plugin and it all worked. But then changed the site some and removed some of the dummy data (Posts, users, & catagories) I had used for site dev. After I did this I got the following message when trying to access the website:

Fatal error: Call to a member function on a non-object in /homepages/44/d219209548/htdocs/cavalier_tennis/wp-content/plugins/social-access-control/social-access-control.php on line 453

If I delete Social Access the blog will reappear. I thought that it must be something in the database that wasn’t deleted when I deleted the plug in directory. I just reinstalled a database from scratch, without any data, but I got the same message. But only when accessing the Admin page of the blog, the rest of the site will work.

I also deleted the plug-in from the Admin panel, thinking that might do a more complete job of removing itself. But I still get the same error message after activating the plug-in and then going to the Admin control panel.

My only option after doing this to get to the Admin control panel is to delete the Social Access directory from the server.

I am a tennis teacher and what I would like to do is have to give private advice to individual students and let them respond if they want. I don’t want them to see my posts to other students I have.

Any help would be greatly appreciated.