Gears Of War Multiplayer Issues

[mastercare]

having just bought the game ..im having loads problems multiplayer side..it updated to 1.1 first of all i assume this was for xbox live...i can join online games ok<although there dont seem to be many> but i cannot host any..it keeps saying i have firewall issues and need to change security settings..well i diabled firewall allowed through ports for xbox live. tried loads diff things but no joy...is this a bug with new patch?
the game itself rocks on the pc.hope this is sorted unless someone knows a work around..
cheers