From http://www.winmxworld.com/forum2/index.php/topic,4981.new.html#new
"At the moment the WinMX Group caches and site are offline, this is because of a decision by the host KM to take them offline. As for why thats not my place to say as I dont know his exact reasoning. For now we are working on getting other caches online and systems in place for cacheless connections.
We will be uploading a hosts file with the known working caches on it, as soon as thats available or more information is available i'll let you know."