Hmm... I don't know what sort of diagnostic tools you have available to you, but it definitely sounds like a problem with the DNS servers you're using. Generally these are provided by your ISP and assigned automatically each time you log on (or turn on your computer, in the case of broadband.) Unless you've got a different setup, complaints to your ISP would be the place to start to really get it fixed. You mentioned that "attmpting to re-route through another DNS" didn't work though. Are you setting the DNS servers on your computer itself to something different, or are you doing something downstream, like at your router/firewall/etc? If it's NOT the server (which it may not be if you're tried different ones) then I'd suspect a virus or some sort of corruption of your TCP/IP stack. Sometimes it can be because of overzealous settings in a security program. Norton Internet Security is notorious for borking the TCP/IP stack... even if you uninstall it, the problem sometimes doesn't go away.
http://www.snapfiles.com/get/winsockxpfix.html is a nifty little tool to repair stacks broken by viruses or software. Give it a go, and doublecheck your DNS server settings. If you know how to, use nslookup to try to resolve xepher.net against various nameservers, including xepher.net itself (by IP address in that case.)
FYI, for an interim fix, you can get to _most_ sub-sites here by the ~username method. Thus, "http://koda.xepher.net/" would become "http://66.90.81.36/~koda/" This method breaks a lot of forum software and such though, so you're likely to encouter some problems using it. Definitely try to sort out the nameserver problem if you can.
