Vivid Carousel Error

I have a big problem with Vivid Carousel. All of a sudden I cannot save changes, there appears a white box with the caption “Fehler” (error), but no other information. When I try to delete (!) the whole block the same error appears.
I have a feeling it has to do with the tokens, but I’m not sure.
The funny thing is I can restore an older version of the starting page, but as soon as I log in in order to edit, the new, not-working version is back.

What version of Concrete CMS are you using?

I’m using 8.5.1, Vivid Carousel v.1.0.1