Do it in an old school way, means i a terminal emulator:
sudo apt-get updateand let me know is fine, please.
sudo apt-get install sparky-backup-sys
Hold on, what backup apps you'd like to install: sparky backup sys or sparky backup apps?
There were 2 spelling issues, that's why the APT coudn't install the app.
Refresh package list and install the latest version of 'sparky-aptus-extra' package to resolve it:
sudo apt-get updateThen try to install the backup tool via APTus again.
sudo apt-get install sparky-aptus-extra