Software :: AMSN On Mac Firewalled Or Behind Router

I don't know much about this. I'll explain it as good as possible: I have a macbook (leopard) and I'm trying to use the aMSN. At first I was able to do it, but then I moved out and it doesn't work here since then. My roomemate operates the windows laptop wirelessly, so do I the mac, but I do have acces to the modem/router. I tried changing the attributes of the router (a westell versalink A90-750015-07 provided by verizon) and nothing happened. Then I read that I could try selecting : connecting using HTTP method, and I finally was able to log in, however I am not able to send or receive any messages. I see when contacts come online but they just don't receive my messages nor I get theirs. I noticed that the connection tab on aMSN says. Type: IP-restrict-NAT and also "you are firewalled or behind a router. So far, none of the methods explained here have helped.