Verisign recently changed the rules on how DNS names are looked up.
Previously, when you entered a domain name that didn't resolve, like "apple", the DNS server would return a "domain not found" IE then responds to that automagically by adding "www." and ".com" around your entry and tries again. If that works, you're in. If it doesn't you get the generic "DNS Error" page.
Now, if you type in a non-existant domain name Verisign will "helpfully" try and redirect you to another site. This is a bad thing and breaks DNS functionality IMO. The solution for you is to start typing at least the .com after the domain name, in most cases the www is not necessary.