How many NICs have you got in your SME server ?
If only one, then the IP address of your SME server must be of the form 192.168.1.x (where x is a number not already used by another PC in your network).
If you have 2, then it depends on what mode you want to test your SME server. If you are simulating a server and gateway, then the external NIC must be of the form 192.168.1.x and the internal nic can be any other private IP network address (ie. 192.168.2.1 is fine). Then, if you are NOT using DHCP on the SME or the CC box, you must set your XP box IP to 192.168.2.y (where y is not used on the 192.168.2.0 network). Otherwise, turn off DHCP on CC and enable DHCP in SME. The configure XP to use server assigned IP and DNS. Release and renew the DHCP address (open command prompt and issue the commands :-
ipconfig /release
then
ipconfig /renew
and you should get an address in the 192.168.2.0 network -- provided of course you get your cabling correct)
Kelvin