Authors are not sharing same accounts, not authors didn’t all of a sudden forget all their logins :) they just all got that message at once when I installed the plugin for S2 (we are talking 10 authors all at once). When I turned it off they could all login. With the admin area not working correctly I can’t change those settings you recommend Christian (the buttons dont seem to work correctly for resetting brute force etc). If we can figure out the issue of the css/js in the admin not loading maybe I can try that.
Yes as I said I turned all plugins completely off for testing late at night to have little impact on visitors (also all the same plugin are in our Beta Site and S2 works fine there). I turned all plugins off except S2 and I also changed themes to the standard WP themes as well.
For W3 total cached DB caching is on. I turned that off and reactivated the S2 plugin. So far authors seem to be able to login, however the admin area still is not loading those links for css and js.
I have the S2 plugin activated now if you want to log back in and see what it looks like and view source on the admin side.