I am not sure why this happens on my Linksys WRT54G2, but I find it strange that I can get into Haven by directly connecting to my DSL modem.
After that, I go into a party lobby, reconnect my PC back to the router and VOILA!!! I can play again, after a brief disconnection and I am still in the party lobby. I could go down the depths and back to Haven without any further problem. Just two or three updates back, I could play this game without any hitch and it is very annoying that I cannot load up Haven just using my router straight up.