Thomas Tschoepke Soares wrote:

I am trying to install mailman here but there are some problems...

So, I have been trying to download the newer beta version but the domain www.list.org even resolv at a ping command!

This is surely a transient failure; www.list.org has been pretty reliable for me. But you're right; I can't get DNS for it either, and I can't ping its nameservers.

The technical contact for the domain is aware and is working on the problem; they have a network outage.