Can't install software due to apt-get check failed

I upgraded to UM 18.10 a few days ago. Now whenever I try and install software via the terminal I get the following message at the end of the operation:

libdvd-pkg: apt-get check failed, you may have broken packages. Aborting...

What does that mean exactly? Things seem to work fine. How to get rid of this error message?

Solved! In the end it was quite simple - thanks to a tip from a friend...

All I had to do was to include the command line:

sudo dpkg-reconfigure libdvd-pkg

That did it!