OK, am finding more and more - that model does not support multicast......
you have 2 options....
1) disable the router/wiresless in it and hook up a compatible wireless router to a eth port on it, and then use the ports on the wireless router (dlink is a brand that i have used for years and have been happy with).
2) set your dsl modem into bridge mode, then again get a wiresless router and set it up with your PPPoE login/pass - your modem will just get you your internet connection in this mode (like a dumb modem, everything would be config/setup in the wireless router).
Option #2 is what I use as I have a Actiontec dsl modem here from Qwest as well. Phone line from wall to dsl modem, eth cable from dsl modem to wireless router, login/password firewall config, port forwarding etc is all controlled from the wireless router. The modem just sits there, in bridge mode the internet led will never light up as it never logs in with your PPPoE credentials because the wireless router does....
It is easy to put the dsl modem into bridge mode also...
Myk