BACKGROUND: When there may be a problem with your DNS, the first step is to check out your WHOIS listing. This is the first step in the DNS process. You get a domain name (say, www.fcc.com) by going to the responsible party for the top level domain you want to be in (.com). For the most popular top level domains (such as .com), you go through the Internic, or someone they have authorized.
The Internic (or other appropriate auhority) keeps a "WHOIS" database, which includes your contact information, as well as 2 (or more) DNS servers that will handle your domain. The DNS servers listed in WHOIS are the start of the DNS process. Those get sent to the root DNS servers, and make sure that anyone on the Internet can do DNS lookups on your domain. When someone looks up one of your domains, the first step (assuming that there is not a cached entry) is to contact one of the root servers to find a name server for your domain.
There are a number of ways to find your WHOIS listing. First, you can try a WHOIS program that runs on your computer ( Sam Spade is a great Windows freeware program that can do this). Or, you can go to a web site such as http://www.whois.net/, or http://www.samspade.org/, or rs.internic.net.
If there is an error in the contact information (such as your E-mail address), it is possible that if there are problems with your domain, it will take longer for you to find out.
Later, we will check them to make sure that all of them are working and authoritative for your domain, and that you don't have extra nameservers not listed here. If there is only one server listed here, you have a serious problem -- contact the company you got your domain name from and get another name server listed in WHOIS.