Can’t ping on peer-to-peer network

I’ve got a two machine peer-to-peer network, both machines running WinXP. Machines are connected to a hub, with an ADSL modem also connected to the hub. Both machines have TCP/IP installed for internet access, and Netbeui for file sharing. I can surf the net on both machines, and I can share files between machines. But I can’t ping one machine from the other!!?? (I’m pinging using IP address) Firewall is turned off on both machines.

When I ping, I can see the light on the hub flicker for the source machine, but not for the destination machine. It seems like the ping gets to the hub but no further??

I would appreciate any help given.