Okay, to DMZ your Linksys you need to log into it. For anyone that doesn't know open up your browser and type:
http://192.168.1.1 into the address bar and hit enter. The address differs per company/router, but that's what it's set for on my linksys. If it doesn't work try:
http://192.168.2.1 For those that have left the router on the default settings on their linksys, type
admin as the password when prompted and log in.
Navigate to the page I've shown, clicking the red circle then the orange one on your router. Those options oughta be easy enough to find if it's not the same.
Now, go to
Start -> Network Places and on the left side of the window, look for and click
My Network Connections Now click the
Local Area Connection link in the window once to select it. Now on the left window again, at the bottom this time, is the details box with your IP addy in it. You need to use the last 3 digits of your IP address and plug them into the DMZ address on your linksys page. Then enable the DMZ option and click save, and you have just exposed your computer to the internet and should be able to play SFC online!
If you still have connection problems then you might need to directly input all the ports needed instead...