Hi. I have just had the same problem. I found that I needed to enable the game's EXE file option to 'run as administrator'.

Just right-click on the 'DoorKickers.exe' file, select 'Properties', select the 'Compatibility' tab, click the box next to the 'run this program as an administrator' item, click apply and Ok. Finally, load the game and in the main screen you should see a message saying the mods are being updated.

This made the mods appear in the MODS section in the main game screen and the individual mod folders appeared in the MODS folder in the Doorkickers Game directory.

The mods are downloaded into the game folder under the 'Documents' folder in your C: drive (C:\Users\ ' your user ID' \documents\KillHouseGames\DoorKickers\Mods\).