To fix the problem of Logitech Vid HD giving a firewall error call failure. It is typically due to a router issue, and the link below indicates there is a way to fix it.
Scroll about three windows down until you get to the post that reads
08-11-2011 10:20 AM
Hello bjackson;
http://forums.logitech.com/t5/Logitech-Vid/Firewall-blocks-incoming-Vid-Chat/td-p/360663