Rather than turn off your Windows firewall, configure it for LW
Firewall configuration instructions (click on link)

Does your modem support UPnP? If it does, make sure it's enabled & then choose the UPnP option in LW's tools > options > advanced > firewall config.
Check out the link below for a bit of info about how to log into your modem & also there's some info about HughesNet/Direcway fair access policy...possibly why your downloads are so slow!
http://www.copperhead.cc/DW7000.htm

Have a look through this thread too, maybe try changing ports & deleting the preferences folder as LOTR suggests
http://www.gnutellaforums.com/showth...ight=satellite

This is all the info I could find about port forwarding for that modem, not sure how much help it's going to be
http://www.testmy.net/forum/t-10610

If you use the forum search to look for HughesNet, Direcway or satellite you might find some help in older threads as well.