Installing the license from the disc.

This is a recurring issue with Steam. You need to somehow stop the download and specify a path on your disk for Steam to install from... I had a similar issue with King's Bounty: Warriors of the North. I don't remember the details myself, but I found an official guide: https://support.steampowered.com/kb_article.php?ref=5357-FSQM-0382&l=russian
Good luck!