NAT Loopback is when you stream video from your PC to livehamcams.com and you cannot see your video on that page and everyone else outside your network can.
Please read the linked article on the website about NAT Loopback to fully understand.
My workaround for this issue is to modify the host files, Do not attempt this unless you fully understand the host files and OS.
The first thing you will need to do is sign up for a free Dynamic DNS.
Next, you will need to add this entry to your host files.
(This would be the local IP of the computer that you have webcam XP running on) 192.168.x.x (This entry would be the free DNS that you signed up for) yourcall.dynamic-dns.net.
Mine would look like this 192.168.1.50 k3bm.dynamic-dns.net
That should work for you if your router does not support NAT Loopback