No route to host means exactly that. This perl script is trying to connect to the server and can't get a response. Its probably using a protocol similar to that a browser would use too, like ftp or http. Except your browser would show you page with a little more information on it. What its saying is that it knows its a valid IP address (destination) (because its looked it up) it just can't get there for one reason or another. This is different to when you ask for something which doesn't exist like www.microsoft-linux.com
Eg. Each little message packet's got a TTL or time to live in it, which is the number of hops or boxen it has to pass through to get to where its going. If it doesn't get there in, lets say- five, then it dies and tries another route.
It could be just contention, like the freeway at eight am.
ping -c 5 <address>
. from a terminal window (command line).
Then you'll know if packets are being dropped. I assume you're not having the same problem with the rest of the world - here for instance. F-Prot probably haven't got it together to allow enough bandwidth for their 'customer' base, or maybe 'somebody' - a busy little security conscious bee has managed to fence themselves in with some new firewall settings? ; ) Only teasing. Can you get to their web-site with a browser?