php warning on instructor capabilities and some courses does not show.

Warning: Invalid argument supplied for foreach() in /web/htdocs/www.abarm.it/home/wp-content/plugins/coursepress/includes/admin-pages/settings-instructor-capabilities.php on line 25

Warning: Invalid argument supplied for foreach() in /web/htdocs/www.abarm.it/home/wp-content/plugins/coursepress/includes/admin-pages/settings-instructor-capabilities.php on line 25

Warning: Invalid argument supplied for foreach() in /web/htdocs/www.abarm.it/home/wp-content/plugins/coursepress/includes/admin-pages/settings-instructor-capabilities.php on line 25

Verified that line on php file. It seems to have no sintax problem.

This problem still persist from december when I try to modify Instructor permissions.

Also I have disabled User role editor plugin thinking on possible conflict, but nothing.

It seems to be another issue: some courses does not show on "page courses.

At this point, it might be usefull to grant admin access for your support.
Thank you
David