Once you open the novetus-windows folder, open NovetusBoostrapper then you will see menus. Click Launch SDK once you are there, click Asset SDK. You will see 3 programs inside of it. You need to find this:
Asset Fixer. Once you are there, click "Browse and Localize Model/Place"
Once you click, go to the folder "novetus-windows" inside of it. You will see the "maps" folder. Click to the folder and you will see "Maps released by year" Choose one of them (which you had problems with the map) Choose the map that is asset missing for you. Now you need to wait to progress. If it says "Done!" you can relax now. Open the same game map and you are good! Have fun with Novetus!