Easy Profile - Joomla Extension

Hi,

We have our site with EasyProfile running fine for some time now. Yet this morning we faced an issue we cannot solve. We are not sure if it is EasyProfile related, but we are convinced it is user related. here must have been some kind of changes in the system that caused this, but we cannot think of any. We hope that you know this type of issue - and the cure for it.

We get blank screens when:
- Loggin in on the back end, right away when the login is accepted. In the database you can see there's a session for the user.
- After loggin in on the front end, trying to edit your profile.
- As a not-registered user, trying to view a user's details. In the url section I've added two urls. The first is an Easy Profile user list, which is working perfectly. The second is one of the links to a user's detail page, from the list.

We've found this error message:
Fatal error: Class 'FOFPlatform' not found in /home/users/vpepnftp/http://test.vpep.nl/components/com_users/models/profile.php on line 437

On this line, it says: FOFPlatform::getInstance()->importPlugin('twofactorauth');
in: public function getTwofactorform($user_id = null)

But we do no use two factor authentication anywhere on the site.