Reports Extension access for role editor

Hej,
I just successfully installed the Reports Extension for the Newsletter Plugin. For me as an admin it is working totally fine.

I then set “Access for editors” to YES, to enable the editors to see statistics. They can see the overview list (as on ../wp-admin/admin.php?page=newsletter_statistics_index) but once they click on a “Statistics” Button WordPress tells them they do not have sufficient rights.

Any ideas ?

Thanks!