Flustered over ICS (Internet Connection Sharing)

[Shadowskater]

Alright well my network is functioning right now but I want it to work a special way. Right now I have my cable modem and router downstairs. The router has 1 connection to a computer downstairs next to it which is running vista, and it is also connected to a printer and network drive which are downstairs, the last connection runs upstairs to a computer running xpPro. The computer upstairs has a motherboard with dual rj-45 connections. What i wanted to do is use the 2nd ethernet jack with a crossover cable to connect to another computer also running xp to share internet and possibly files and drives. Using these two guides Link1 and Link2 i have came up with an understanding of what needs to be done, but i just cannot seem to get it working properly.

Alright the main problem. When i go to enable ICS (internet connection sharing) on the host computer for the connection that is functioning, i keep getting the error,

"An error occurred while Internet Connection Sharing was being enabled.

Internet Connection Sharing cannot be enabled.
A LAN connection is already configured with the IP address that is required for automatic IP addressing."

I understand that this problem is due to the address 192.168.0.1 needs to be open for ICS to function. So i manually set my router to have the LAN at 192.168.0.101, so now when i ping 192.168.0.1 it comes back timed out. Yet it still does not work!

I am terribly confused now and have no idea where to go from here, thank you in advance to anyone who read this through or attempts to help me in any way!