I got this from my MCSE course material. Hope it helps. I think you may have a packet filtering problem. See "Request Timed Out" below. Sorry I don't have time to research further, but Help in 2000 + Microsoft Knowledge Base should be able to provide the rest of what you need to do.
Scott
Routing Problem Error list
* Request Timed Out. Indicates that no "Echo Reply" messages were received within the default time of one second. This message may be the result of network congestion, failure of the ARP request, packet filtering, a routing error, or a silent discard. Most often, it indicates that a route back to the sending host has failed, because the destination host, one of the intermediary routers, or the default gateway of the destination host does not recognize the route back to the sending host.
Check the routing table of the destination host to determine whether it has a route to the sending host before checking the routing tables of the individual routers. If the remote routing tables are correct and contain a valid route back to the sending host, use the arp -a command to determine whether the correct address is listed in the ARP cache. In addition, check the subnet mask to ensure that a remote address has not been interpreted as a local address.
