Plugin cant be installed because it causes fatal error

I work with WP 4.2.3. When i try to activate plugin i get this message. And activation is terminated. What can be the case? I deactivated all of the other plugins. The only thing that is different from the standard install is the roles, apart from admin, they all changed? can that be the reason? Which roles doest it need to be available?

http://wordpress.org/extend/plugins/user-meta-manager/