ok, to sum up (for non-portuguese speakers):
servers added by DNS doen't work in aMule (for example, adding sado.kicks-ass.net ). So, you must get the server's IP.
You can easily get the IP by pinging it:
command-line$ ping -c 1 sado.kicks-ass.net
PING sado.kicks-ass.net (81.84.96.18): 56 data bytes
So, the IP is 81.84.96.18 and that's what you have to add.