Start by opening up the control panel:

OR in classic view:

From there, open up the network connections:


OR, in classic view:

Find the network connection for your network card. There could be more than one, so you have to know witch one you are going to be using:

Once you get to the properties, scroll down to the "internet protocol TCP/IP" and hit properties:

Put in an IP address similar to this one, if it gives you an error about the IP address is already in use, then just start couning up or down, so if 192.168.0.100 is in use, try 192.168.0.99 or 192.168.0.101:

After clicking OK to save your settings, open up FlashFXP and go to the Quick connect screen, either by clicking the button or pushing F8:

When the Quick connect dialog is open, put in the IP of your xbox, as well as the username xbox and password xbox:

I hope that helped.