I did have it working once, and did not change any thing in between then and now.
If you have installed and running a virtual network device like Hamachi in the past, and not turned it on when testing now, your HFS will not work correctly.
I run Hamachi on my computer sometimes for creating a virtual LAN. God for LAN gaming thrue the web.
If you really want HFS to work, and work your way around your ruter problems, you can install Hamachi.
But to have your friends to accsess HFS they also have to install and running Hamachi.
Did your Loca Area Connection get an ip starting with 8x.xxx.xx.xxx (and NOT 192.xx.xxx.xxx or 10.xxx.xx.xxx or 139.xxx.xx.xxx ) after your ipconfig /renew ?