Hi Uwe,
I just installed that plugin for testing, and there seems to be an issue with their latest release, affecting other plugins as well. The cause is indeed an fatal script error, and others have reported is as well: https://wordpress.org/support/topic/v3-7-5-gives-issues-with-yoast-and-backupbuddy-plugins/
I can see this error all over the WordPress back-end, even on a fresh WordPress installation without plugins. I believe the author will release a fix for it very soon, as it will affect all of their users.