I wasn't trying to be either rude or condescending; I was responding to what seemed to be a lack of understanding. Administering a public DNS server is a non-trivial undertaking. When your response to my (paraphrased) "there's no DNS record for your host" is (paraphrased) "what do you mean by that?", it seems that you're missing a basic understanding here.
Now, as it happens, the problem goes deeper--neither your primary nor your secondary DNS server is responding to DNS queries (in fact, the secondary doesn't even respond to pings). Based on their IP addresses, I presume that you're responsible for both of them. Based on the fact that the IP address for guido seems to be the same one that you're using for www, it looks like you're trying to use your SME 5.5 box as a public DNS server, which it isn't designed to do (and I'm not aware of any HOWTO for adding that feature to v5.5).
Your best bet is to have somebody else host DNS for you--zoneedit.com will do it for free for up to 5 domains, and has an easy-to-use web interface for updating their records (and it happens to be what I use). If you're set on running your own public DNS server, try searching here for public dns; you may find some helpful information for 5.5.