There is nothing odd about one machine blocking ping and traceroute and another not blocking it. The common reason is to keep the network topology behind that router private or to mitigate some forms of ddos attacks.
If you don't believe me feel free to try and traceroute from here, you'll get the same result.
http://centralops.net/co/
Here is some more info:
http://serverfault.com/questions/255...m-and-ebay-com
http://superuser.com/questions/27895...-traceroute-it
What client are you using? Does it give an error or is the list just blank?