Nonstop-Backup problem in Build 6525

I configured a nonstop-backup for my databases and everything worked fine for weeks.

After updating to build 6525 the icon in the lower right corner says nonstop backup has been stopped.
Reenabling isnt possible. Acronis tries to backup but doesnt work (blue icon instead of black).

So I deleted the backup job including data and directory and created a totally a totally new one.
The result is the same. Even after opening Acronis and pressing "backup now" on this job it calculates only the remaining time - but never starts.

Where can I download an older version of the program without this problem/bug (?).