That would most likely your antivirus program (or even browser itself) blocking the download since it's an extractable file from an unknown source - they're quite careful with that usually.
So either check in the options if you can whitelist this page or just turn it off for a short while when downloading mods.

However, if disk space isn't a big issue for you I highly recommend using our Autoupdater (the download of this will probably also be blocked, so see above), which will download and install all of our content automatically and allows you to drive on our online servers without any mismatches due to missing mods/skins etc.
The final Kölschbierbude install with all of our mods would be around 27GB in the end.