The default URL for the GeoIP.dat database is broken, it returns a 404 Not Found (October 2024):
http://www.maxmind.com/download/geoip/database/GeoLiteCountry/GeoIP.dat.gz

I tried to configure an alternative URL into downloads.ini, the one I found is HTTPS:
https://mailfud.org/geoip-legacy/GeoIP.dat.gz

Unfortunately it seems that MLDonkey is unable to use HTTPS; after configuring the URL above, I sniffed the traffic toward the target server and I see a TCP connection to TCP port zero instead of 443. Even though I explicitly declare port 443 in the URL, the connection does not happen.

Maybe MLDonkey is not HTTPS capable at all, can be related to issue #41 too.