Greetings,
Don't mention "pings" , just say you need to configure your LAN instead of that while you state your problem
Now,
You also want to share InternetConnection/n' serious stuff or just to configure succesfully your LAN ?
If yes , ( you said winXP/linux and viceversa ? )
Try to configure your Ethernet card , via DHCP on linux
(You know ip static or auto via DHCP | (((Host/Domain)NAME)/DNS) )
Or viceversa via DHCP on win and see where you go from there
| domainname | dnsdomainname | nodename | hostname | or whatever to make sure everything's in order
Farewell