I found the answer, and i thought I would share.
If for some reason users are not able to login, the problem is probably Active Directory. Sometimes the Admin password will not work, to resolve this you will need to log into the mysql database and fix this there. go to "mysqladmin", and login. You will then go to the database "your database', and then to the table "wp_options". In this table you will find the field 'option_name' that is "active_plugins", click on the pencil to edit. Delete i:0;s:47:"active-directory-integration/ad-integration.php";.
Now your plugin has been deactivated, you can go and change your admin password. Go to your table "wp_users" and find admin, which is usually row 1. Edit this record. In the user_pass field, which is encrypted put your password, change the function for the password to MD5, then save. Now your admin password has been changed, go to central and login with your admin username and password. this will allow you to do anything in the backend. You can now turn the ad integration plugin back on.