NEWT uses the same function as DOS ping to find live remote IPs.
Could you paste in a message what you\'re seeing when performing a DOS ping where NEWT was unsuccessful?
Also, you\'re using version 2.0.2284, correct?
As for the XP/SP2 machines, could you check one of these locally and make sure the XP firewall isn\'t turned on? As I don\'t believe the firewall can be controlled through policies on a Win2000 based domain.