windows xp sp2 won't save Ip address

I have a strange problem: I followed the limewire instructions on how to open a port for the gnutella network in the firewall of windows xp sp2. it worked for a day. the next day, I would not get a connection to limewire and when I checked the settings on the firewall and the port, I found, that in the field of the IP address there was my computer password. That's why I wouldn't connect. I changed it again to the correct Ip address. still would not connect. check again what's going on: there is my password again in the field where the IP address should be! what the heck is that??? why does my computer replace the ip address with my password and doesn't save the damned Ip address???? anybody any ideas on that????